Retainer wont fit anymore- can i make it fit

Won't work. You should have worn your retainers as originally instructed.
You teeth are moving to their original position that they were in before treatment i.e. Relapsing treatment.
No matter how hard you try, your retainer won't fit.
You need to see your dentist ASAP and go from there.

ahhhhhhhh idk but i had teeth removed before because of the overcrowding, so they have moved a bit but havent moved back to their original positions (because the teeth are gone),, do you think they might just stop moving further now?

So you have teeth extracted thereby creating space for further treatment to align your teeth because I'm assuming they were misaligned due to their crowding. Your teeth are moving all the time more so, if you're had orthodontic treatment in the past. If you don't wear your retainers, your teeth will move back to their original, pre-treatment position. Unfortunately, they won't ever stop moving unless you wear your retainer like you were instructed to.a

You need to see your dentist who might refer you to the orthodontist depending on how old you are and how much treatment relapse you've had.

So how come my teeth haven't moved back even though I haven't worn my retainer for about 5 years?

Unfortunately I don’t think that will work! You’ll just be forcing the shape of the retainer rather than re-aligning your teeth. Go to the dentist and get a new one made for your teeth shape now, that way you will prevent them from moving any more than they already have.