How bad is it to take 30-50mg of codeine a day

Dou you really have a healthy lifestyle or do you have disordered eating and a problem with alcohol?

Do you suffer with stress/anxiety at all?

I would look at doing all you can then to reduce your stress and anxiety, stomach ache is a very common result of stress and stress is a common trigger of headaches. Not being able to get to sleep as well of course is also related to stress/anxiety. If you can sort out your stress/anxiety levels then I bet all your other issues would be solved or much reduced. Codeine also often gives people a feeling of well being - you might also be inadvertently medicating your stress and anxiety with it. I'd go to the doc and get help with your stress and anxiety and stop the codeine.

Relatively healthy, I eat a lot of fruit and veg and I have genuinely tried all the things doctors have suggested

That was me. I buy it from the two different pharmacies in my area, and now from 3 pharmacy websites and if I’m getting the train home from uni, I get off at every train station that has a pharmacy

There is a lot more to a healthy lifestyle that eating a lot of fruit and veg. Being underweight and drinking every day are certainly not helping your lifestyle and your pain issues.

Going to two different pharmacies without telling them you're going to other pharmacies to buy it in then going to three different pharmacy websites to procure it and then getting off at multiple train stations to stop at different pharmacies to amass a stock of codeine doesn't exactly sound like the actions of someone who doesn't have an addiction does it...?

I’m not doing all of that on the same day, one packet of 32 takes me about a week

It's not about the amount you're using I'm pointing out (that's an issue others have already mentioned), it's the behaviour patterns.
Do you think it's the kind of thing people who don't have a dependence issue do? Even if not on the same day, you're going (literally) out of your way to procure more to feed the need for using it, you're also doing so in a way that obscures what you're doing (I am assuming you aren't telling any of these pharmacies what you are doing), from the professionals you are dealing with - and you don't seem to have any awareness or insight into that.
How do you think the pharmacies would respond if they were aware? Or your GP? Do you think your family and friends would consider that the normal, healthy behaviour of someone without a dependence?
I think you may not be fully recognising just how far into this hole you may have gone. Consider if someone was doing this with alcohol - going to multiple different shops to avoid being recognised buying alcohol repeatedly, misleading the people selling it about how much and how frequently you have bought it, and not having any insight into that not being healthy behaviour. Most would consider that to be a sign of alcoholism.
By extension then I think it's not surprising that this does seem to me and others to be the behaviour of someone with a different substance abuse/dependence issue - in this case codeine.

OP clearly has a lot of issues and based on past threads, I really don't think the efforts of you or anyone else here is going to change what she does. Don't waste your time - she is not in a place to accept this is a problem.

It's not about the amount you're using I'm pointing out (that's an issue others have already mentioned), it's the behaviour patterns.
Do you think it's the kind of thing people who don't have a dependence issue do? Even if not on the same day, you're going (literally) out of your way to procure more to feed the need for using it, you're also doing so in a way that obscures what you're doing (I am assuming you aren't telling any of these pharmacies what you are doing), from the professionals you are dealing with - and you don't seem to have any awareness or insight into that.
How do you think the pharmacies would respond if they were aware? Or your GP? Do you think your family and friends would consider that the normal, healthy behaviour of someone without a dependence?
I think you may not be fully recognising just how far into this hole you may have gone. Consider if someone was doing this with alcohol - going to multiple different shops to avoid being recognised buying alcohol repeatedly, misleading the people selling it about how much and how frequently you have bought it, and not having any insight into that not being healthy behaviour. Most would consider that to be a sign of alcoholism.
By extension then I think it's not surprising that this does seem to me and others to be the behaviour of someone with a different substance abuse/dependence issue - in this case codeine.

I don’t think it’s normal and I’m well aware they wouldn’t sell it to me if I said that’s what I’m doing

So why are you resistant to actually speaking to your GP about this and other problems?
Nothing is going to change if you don't engage with the issue.

OP clearly has a lot of issues and based on past threads, I really don't think the efforts of you or anyone else here is going to change what she does. Don't waste your time - she is not in a place to accept this is a problem.

Based off past experiences with doctors, it wouldn’t help anything. I’d go in there and tell them I take too much codeine and they’d say just stop doing that then without actually giving me an alternative. It would also make it easier for them to dismiss me as some sort of drug seeker or as making things up.

Stop focusing on the past and just focus on the now and act accordingly. See a doctor and talk to them about the issues and go from there.

This is a completely separate issue from past threads though and none of the other stuff really needed bringing up at all

This is a completely separate issue from past threads though and none of the other stuff really needed bringing up at all