Did your doctor only perform a urine screen to see if you're pregnant? A blood test is more accurate and can detect it sooner than a urine test. also, by the sounds of it, your periods aren't regular in which case it is a little more difficult at times to keep track n detect pregnancy with simple OTC tests. If I haven't seen the OB/GYN since the last time, maybe u should schedule another appointment and if you're 3 months along, it's a bit soon to be feeling fetal movement.
Go get blood work or an ultrasound done?
If the pregnancy test is neg then ur not pregnant. By now ir would've been a very clear line but the latest was neg n it's been too many days since ur last period. I would still go to the doc to get check cuz if ur period is that off n ur belly is growing (if ur not just eating junk) then it might be something else. Maybe a growing cyst or tumor or something like that. That needs treatment. But I definitely don't think ur pregnant. On the symptoms telling by the amt of test u have taken, they might just be causes by the stress n u thinking u might be pregnant.