Why my temperature is getting higher?

I've finished my ovulation 4 days ago and my period will start on the 4th of February, but my temperature is getting higher yesterday was 36.8*C/98.24*F and today even 37.00*C/98.6*F. Last night I had some light pink spotting. I'm sexually active and always use protection except for one day during my 4th day of period this month on 6th of January... women such a strange creature!