Reason to worry?

My Bf and I had sex, kinda unprotected (withdrawl:blush: ) on the 24th and 25th, my period was due on the 26th. This might be navie of me but i didnt think you could become pregnant that close to your period. I’m late now, not too late, but i am a little worried, because i havent gotten the normal signs that my period is coming, which i get everyy month without fail. I’m most likely freaking out for no reason,I havent got any pregnancy signs, even though it would be to early for them anyhow. Though ive started to feel sick the last few day, nearly threw up at work, but i think that was something i ate.(cant eat gluten)..can you tell im confused?:P. I would like to know what you guys think. Do i have reason to worry?