Weird BBT

I've been TTC for about 3-4 months but just recently started monitoring bbt. I have not read much about it except that you are supposed to get a spike when you ovulate. I started taking the temp while on my last period. It first dropped as soon as period was over. Then I had a spike about a week later. Now I have another spike. I'm "supposed" to ovulate in about 4 days according to calendar. I've been taking temperature first thing in the morning to be constant. Has this happened to anyone else out there? I have no idea if I should take today as ovulation day. Soooo confused. My bbt graph looks like a roller coaster!