Am i pregnant or not, if i hv protected sex and negative result from home pregnancy test~

hi~ i am 19, and i had sex with my bf few times lately... my abdomen is like getting fatter... im not sure if it's because i am just getting fatter or it's because i am pregnant so i gain weight??? and plus.. last month i kind of got two period: Jan 7th-12 (this one was normal) and Jan 22ish to 28 was really light period... and this month.. i hvn't get my period yet...
and my lower abdomen sometimes hurts...it feels like pain before a period come or during the period

i did a home pregnancy test last Tuesday and it showed negative...
and i did another one again yesterday morning.. and it shoed negative again...... but i still worry.. and my bf went back to his home country....