Im gonna make this as short as possible. i had unprotected he said he *** in me a little bit. right after?

right after i began to feel sick and nauseated, bloated(real bloated). but i just thought that i was getting my period. so i got wat i thought was my period pretty normal i suppose, so after that was done normally my will go back to its reg size and no more bloated stomach, but now im still tired and i eat way too much and im getting a little bigger in the backside. this week when i wiped myself i had a pinkish discharge and then brown.so my question is do you think it could have been a breakthrough bleeding that i experienced? can i be pregnant..dont worry im going to see the doc next week.oh and now im so constipated smh wat is this