this is the ovulation thermo I've got. had to go to a few chemists as nobody had them in stock and they eventually had to order one in for me! but they're cheap and easy to use. you'll need a special ovulation one that detects temps to 2 decimal places.
I'd just take mine when my alarm went off at 6am (you're supposed to do it before you even leave bed as it's supposed to measure your resting basal body temp) and record it to fertility friend (a lot of ladies on here also use ovia). hopefully after a couple of months you'll start to see a pattern.
at least if you're NOT ovulating, you'll have some concrete evidence to go talk to a doctor about as I reckon that's potentially what they'd tell you to start doing anyway.