I think I might be pregnant...?

ok, here's what goin on...about a month or 2 ago i thot i was preg, i had missed my period and was like 8 weeks late. i took a at home test and it came back neg but i wasnt convinced because i jus didnt feel right and i kept getting sick at night b4 bed. then, bout 9 weeks after my last period, i finally had another one but it wasnt as heavy and was only 3-4 days instead of 5-6. a few weeks later i took another test jus to make sure and again it was neg. but lately ive been getting really sick and light headed randomly throughout the day. my are sore and sensitive and ive been goin to the bathroom alot. ontop of it all i swear my stomach is startin to gett bigger altho i havent gained any weight yet....my question is could i possibly be pregnant even tho the tests say no?