Early pregnancy?!!

I had unprotected sex with my husband 4 weeks ago (we are in the process of moving house so we haven't actively been trying but also we do want a baby so...) ANYWAY... I had my period around the expected date (I'm never clockwork) & it seemed fairly normal- perhaps a little lighter than usual and lasted 5 days instead of 7 but it seemed (at the time) normal. My breasts were tender around this time but this has eased like it usually does. About 3 days ago I started to feel nauseous and thought I must have a bug, but I haven't been sick. Just feeling on the verge of being sick- for the most part of the day. It's not waking me during the night and I am able to stomach toast. I've also been feeling "wet" down there.. like my period has started or something. It's making me paranoid and I keep running to the loo! It's nothing just a clear liquid?! I wondered if anyone else has ever fallen pregnant but had bleeding like a period? TIA xxx