So sensitive!..

So I was on the combined pill for 3 months and decided to change to the mini pill.. I had sex the first day of changing pills over and I have had horrendously sore nipples for about 1-2 weeks and now sore breasts too which have only started today.. I have also had nausea about the same time every week for 1 week and hot sweats!? Is this normal? I plan on taking a pregnancy test, but how high is the posibility of being pregnant?