I really believe I ovulated, but no temp rise. :(

We've been trying since last June and it will be our second child. With our first we conceived so quickly, but I really think we aren't timing it right this time around. I've tracked my cycles and occasionally won't ovulate or I will ovulate and I won't notice ewcm. Last Friday I had a ton of ewcm and then by Monday my temp went to 97.1 and my breasts started hurting like they always do after ovulation. Plus I no longer had ewcm. I expected a big jump on temp Tuesday 2/11/14 but only saw 97.5 and again 97.5 on Wednesday. Ugh. Does it have to be a big jump in temp to mean ovulation? Thanks for reading.