Maybe Ovulation

My period was on the 19th-23rd Of February. My fertile window started today according to glow but I feel like I am ovulating right now. I have cramps on my right lower abdomen, nausea and feeling sorta light headed. That’s what happens Everytime I ovulate. However I took an opk yesterday and it was negative. Also I am not able to do bbt charting because I work overnights so my sleep habit is sometimes wacky. What’s going on?