What Could Cause Delay In Periods And Pain In Stomach?

i am 24 years leady i missed my periods from last 12 days & i am getting pen in my stoumach at down when i wash the clothes what do you thin i am pregnant or i will get my periods & yesterday when i had sex with my husband i didnt got that feeling that i use to get normally it didnt gone very deep.
Pls revert............