Citalopram help please!?

Im on 20mg citalopram daily. Am on day 10 now. First few days i was waking at like 5.30am and not able to get back to sleep and also i had no appetite (slowly coming back) but my biggest problem is that i am SO tired. and i dont just mean tired i mean my legs and arms ache and i can barely move them. If we are out and about i have to trudge along but if we are at home i have to sit or lay down just to rest and find myself nodding off. I also find myself falling dropping off if we are in a pub or restaurant. I take my tabs daily at 10am and the fatigue seems to wear off bout 5-6pm but from when i get up till this time it is a nightmare. Is this normal? especially as i am now on day 10 and thought they should be kicking in now. My mum was on these tabs and says this is a common side effect but im worried its being caused by something else. I am on these tabs cos of minor depression and stress but mainly for obsessive thoughts caused by health anxiety so am quite worried. Any insight much appreciated. I am so tired just getting in a morning is a chore lol