I'm 22, And New To Charting. I'm About To Get

i'm 22, and new to charting. i'm about to get married and trying to avoid pregnancy. my question - my temps before ovulation seem to be all over the place. last cycle i knew when i ovulated b/c i had some spotting and my temp increased and stayed up. this cycle my follicular temps were up and down, and i think i ovulated but am wondering why my follicular temps are erratic and if its a potential problem