What Are The Early Signs And Symptoms Of Pregnancy?

Hi, I had intercourse on December 25th and the following morning I had morning after pill. That month my period was a bit earlier and lighter. I know that can be the pills side effect. but this month I had my period on Feb 2nd and ended on Feb 3rd. I had intercourse on Feb 4th morning. I know it is not much possible to get pregnant right after the period. Around these days must be my ovulation time but I am showing unusual signs ( normally I have these signs just 1 week to period not 2 weeks earlier) swollen sensitive breasts, nausea, vomitting, very tired all the time yawning, chills and hot flushes esp during sleep time in bed and these are still going on. Few days ago I had a strange pressuring pain at the end of my tailbone and lasted for almost 2 days.So these are caused any infection, just ovulation, still the Mornign after pill or pregnancy or something else? thank you