First month tracking BBT

I'm just sitting here trying to decide whether to buy a pregnancy test. This was my first month tracking bbt, and I didn't see any major spikes in bbt until five days after the day that Glow claimed was my ovulation day. I was figuring that AF would just be later than Glow said (which would mean we BDed at the wrong time). Today was the day AF was due, and my temp spiked UP. I have a tiny bit of brown spotting so far. Should I just wait it out until I see whether this is AF, or buy a pregnancy test? (I know I should almost certainly wait but I am driving myself crazy over here!)