how do you know you're ovulating without OPK or BBT?

And... can you have pregnancy symptoms during this period?? on Glow, it shows you're fertile by displaying green, but how do you know otherwise?? My husband and I had sex, and the following day I had clear CM outside my fertile window. A few days later we had sex again, twice on the 2nd or 3rd day in my fertile window (mild discrepancy between apps). This second round was only a few days ago but I've been having mild cramps, and I've never gotten ovulation cramps. I also had a wave of nausea, which is really strange. Thoughts?