Hmmm...I had a cycle once where my temps stayed up, was not pg, but I didn't have my period. I had an ovarian cyst- you might look that up to see if you could have one and still have your period.
Other than that...hmmm...it's possible (but probably VERY unlikely) that you could be pg. I have a friend who had her period for 3 mos after she got pg. I didn't get a +pg test until my af was 1 week late (so 20dpo)
Or there could be something else going on. Maybe you're sleeping differently, and that's affecting your temps?
Becky, partner to Teague, SAHM to Keagan (7yo), Jonah (2yo)