Someone HELP please.

Okay so I use to be so irregular but the past year in a half I have been coming on every month at rhe end of the month 7 day last. Well the last two month last month & the month before I started at the end but they only lasted for 4-5 days that's it! Okay now getting to where I need help. I'm in my window time have two days left didn't even know I was in my window time area at all either. Will yesterday I had sex with my boyfriend foe the first time no condom and he came twice I know for sure he came once inside me cause he told me. But I'm not sure about the second one it really don't matter but anyways. Today we had a sex again no condom but he didn't come inside this time. Like I said I didn't even know I was in my window time this week and I'm not on any birth control but I have a many problems I don't think I can carry. Okay today my stomach his cramping like I have a lot of pressure kinda in my lower stomach I feel really bloated today as well. Can someone please tell me why in the world did I wake up feeling like this. I know it's way to early to have signs of possible pregnancy so why do I feel this way ?