bbt calculator and opk q opinions plz

[ms sunshine]

hi im dpo 12 and im wondering if anyone has used calculators and it has messed up your temps so your are out when you apparently o. reason being i normally have a 33 day cycle. i started taking red clover blossom which helped me conceive my first but didnt really alter my cycle. this time round it has made my cycle shorted if you believe my temps. as today is cd 25 and af should be tomorrow. i did get cm roughly that time but hard to tell the difference between sperm and cm i guess. as for opks i left one too long before checking so i am not sure it was positive the second i know was positive and i did get a temp increase. i normally wake up between 2 and 4 am and thats when i temp and i get up at 6 but between wake and get up is normally broken sleep with my 2 yr old son. next cycle i am just going to try and take it at 2am but im just wondering if anyone has had bad experiences with calculators? i just want to make sure i am o'ing when i think i am. i should be o'ing now if my cycle wasnt shorter and i just did an opk and wham its positive. i dont know what to think. surely a calculator cant be that far off. im hoping its just the red clover shortening my cycle. i have af pains so makes me think it is due just weird how its positive does anyone else get that?

My Ovulation Chart