Bbt confusing me!?

hi, i'm hoping someone can help me with this, i've been charting my bbt for a while now and i noticd that my temp dips usually the day befor my period is due and stays low on the day i am due aswell. i have a 29-30 day cycle and ovulated on cd15 this month and had on day 14,15&16. anyway this month the 1st unusal thing i noticed was that my temp did not go up straight away after ovulation ( i know i ov'd because i used an opk i also got a temp dip the day i tested positive of 36.1 ) but stayed low for 3 days after of ovulation at 36.4, it then shot up to 36.8 36.9 and has stayed around there. i am now 14dpo and when i took my temp this morning i woke up much earlier then normal, i took it at 5.30am when normally i take at 6.45am, anyway my temp was down to 36.3, so i must be getting my period, i then fell back asleep for 3hours took my temp when i woke up at 8.30 and it was 37.0. what does this mean and which one is more right?i