Could I be pregnant?

[SP19903]

I know the most obvious answer to that question would come from taking a test but I think it's too early for that. I was just hoping for some insight/advice.

Myself and my partner had unprotected sex on the 26th of August. I had just finished a 2 month course of the contraceptive pill (I think I took the last one on the 24th-though I wasn't entirely consistent through the month) I did have a period roughly starting the 29th of August. However, compared to my usual cycle it was extremely short and lighter.
Anyway, I haven't thought much more of it until today when my breasts feel a little tingly yet not tender or swollen. However, my gag reflex has felt sensitive all day. Almost like there's something constantly sitting right at the back of my tongue, my stomach feels a little bloated and I'm more gassy than usual. I'm not peeing anymore frequently, however I drink mainly coffee and nothing else.
I know I'm probably just freaking out a bit, but anything to put my mind at ease would be great.