Want I think you should tell your GP how you feel. Pregnancy can really bring on some strong hormones and if you are feeling anxious, this can get exaggerated. They really can help!
I suffer with anxiety myself (although fine at the moment) and I also was diagnosed with OCD but it only becomes bad when I am stressed out or hormonal. I have had a mental health assessment, so they are aware should I start going downhill but not realise it myself.
My partner is also aware which is reassuring.
They won't start doing anything you don't want, and sometimes just talking about it really is enough!
misseskimo my son was 9lb when born and 57cm long, he was too big for Newborn so all that stuff was returned - my daughter was shorter but 8lb 2oz and Newborn was fine for her for a few weeks.
I don't go on weight, more length but I guess there is no guide for that.
If you are tall or your partner, i'd go straight for 0-3, having grows which are slightly big won't hurt.
Finding the nausea really difficult some days, last night had dinner and spent about an hour thinking I was going to throw it back up! Haven't been physically sick for about 2 weeks now, but the nausea is constant. The only thing I find that helps is strawberry flavour extra chewing gum.
My bump is obvious today, someone pointed it out earlier 
9+4 (scan) 10+4 (dates)