Citalopram was also the first antidepressant I was prescribed, and was told to take it as soon as I got home. I really was in a bad, bad place.
Side effects are totally normal and only last a couple of days - but it can be a few weeks as its different for everyone. They may not totally disappear, for example the insomnia and didrrhoea, but if you mention it to your GP on your next appointment he'll keep a track of it all. However, I soon changed the drug. I'm on my 7th type of antidepressant (yes, my 7th…) having tried each with 3 doses. I am, admittedly, quite seriously depressed, unable to see other family and haven't seen any of my friends for about 1.5 years, and anxiety of leaving the house is becoming a big problem.
There are alternatives to medication, as well as taking the medication at the same time such as CBT. I'm having my second shot of it and currently have just started Prozac, which I suspect my dose will be increased next week.
I seem to remember had very similar side effects with Citalopram, like you. If you are worried, contact someone. Anyone. Whether it be a medical person, friends or family - someone to watch over you if your that worried. Your doctor is also correct of how long the drugs will take to kick in. You may feel worse before you feel any better
I, like many others, totally understand how your feeling.