"Normal" BBT

Hey Ladies, just a strange question... Is it possible/normal for your "normal" bbt to change? Either by season or just over time?

I used to chart my temps but found it and the TTC to really stress me out and drive me crazy so I stopped (we've been TTC for over a year, haven't regularly temped since September)

My question is because I randomly took my temp this morning and it's a bit higher then it used to be but not crazy high. AF is due Friday and trying not to let my thoughts and hopes get the best of me but I'm not very good at that lol