I had sex with my boyfriend on Monday and he came inside me but I had my period... could I be pregnant?

My sister in laws fourth child was conceived while on the last day of her period. So yes, you can conceive while on your period. I think it is unusual for a woman to ovulate while on her period, but it is possible. I also got pregnant with my third child, after having sex where He pulled out before ejaculating. Unfortunately, there are many myths out there that are not true. If you don't want to be pregnant, or get a disease (many sexually transmitted diseases are now transferred through skin to skin contact), you should be abstaining from sex.

I've started feeling pain in my stomach and I've been feeling sick like I'm getting a head ache and I'm tired a lot so I don't know if my mind is playing tricks on me but coud this be signs?

It might be your mind, or you might be pregnant. I would wait a couple of days and if you are still feeling signs either go see a doctor or get a home pregnancy test.

Cause Ive Had My Period For Over A Month Alreadii I Got It Three Times And There Were No Signs Of It No Cramping Or Anything And Its Very Light And Brown And Sometimes It Go Heavy Not All The Time And Its Still There I Mean Im Not Eating A lot And I Dun Throw Up Or Anything I Guess Ill Wait Till My Period Goes Away For Good And Then Ill Take The Test Thank You