Finding BBT stressful.

Hi all. I started using OPK this month and doing BBT. I wanted to really lower my stress of trying to fall pregnant and really pin point ovulation as it took 15 months with my daughter. I found OPK great and took stress out of BDing knowing when we exactly had to then would BD other times whenever we felt like it.. im really struggling with BBT though i dunno if i just dont understand properly yet what the temps mean or what im looking for, if im doing it wrong as my temps are erratic!! Im finding it stressful. I want to not do it but thiught would help my obstetrician in couple months when i go back.. any advice? should i pack it in and just use cm for the obstetrician to go by? I just dont want stress to prolong everything. Sorry for my rant and long post just feeling confused and deflated. I fell preggers with my daughter when i stopped trying and packed it in 😧 i dont want to not try 😢