I've had unprotected sex on 25th Dec 2016 twice in a night since then I started experiencing nausea , vomiting , lower back pains including lower abdomen pains. Then had period 13 Jan 2017 lasted 4 days. I had a pregnancy test twice both came back negative and blood test with no result if pregnancy. I'm now 9 days late on my period and been having brown / on and off light pink spotting when i wipe after going to the toilet every 10 mins don't know whether it's my period coming , feeling confused. I will be going for an ultrasound next week. Feeling confused at this stage. Please help need to know what's happening.