My temp in my bedroom is aways different too. One night our ceiling fan will be on and the next it wont. So once you get started it will work itself out. You really should get a BBT they are more sensitive. I got mine for like $8 their cheap. I can help with any questions too. I stopped charting shortly after I got my BFP because I knew I would worry if here and there my temp went down.
Sucks that AF showed up today of all days but I know that you were waiting on her so its good she finally came. I've had cycles that lasted 46 days and it really sucked.

HAPPY BIRTHDAY TO YOU, HAPPY BIRTHDAY TO YOU, HAPPY BIRTHDAY DEAR BRITTANIE, HAPPY BIRTHDAY TO YOU