Can I be pregant?

My boyfriend and I had sex on the 15 Feb, We used a condom and I'm 100% sure it didn't break , I stopped him before he could ejaculate. I have missed my March period, during last month ( March) I took 2 home pregnancy tests that both came out negative ? What could be the problem ? Please help !!

Missed periods are not uncommon in teen age and older, pre-menopause females. If you have started a new hormone based birth control method or have been under a lot of stress, that could be the cause. If you miss three periods in a row, see a doctor.