cumed in me !!!!!!!!!!!

so today was a normal day went to work but i wasn't feeling well so I left early I'm 17 18 in February btw so after I came home I told my boyfriends who I have been with for 3years nearly 4 to come round and we always lay in my bed and watch tv well my mum and sister went out my brother was in the bath so we thought why not have sex we always use a condom but because we didn't really plan it we never have sex at my house so because we didn't plan it he didn't have one anyway the point to the story is that he cumed in me I start my period in 3 days but I know I will still get my period this month even if I'm pregnant because it was to close together so does that mean if i get pregnant I will miss next month period ? and no hate comments I know it was foolish of me to do that but I think we will be alright we both have jobs and a great family who will support us not financially wise I would never ask for that but just to be there for us thank you for reading this I would love to read your comment and opinions thank you