Ovulation spotting CD 10??

Had sex last night, I’ve been cramping the pst few days, went to the bathroom and it’s super stretchy cm, and I’m spotting. I don’t do ovulation tests, my husband and I just started trying and we don’t want to buy tests for a few months, I got nexplanon out end of February, chemical in April, my cycles have been 28-35 days long so i have no idea when I ovulate. I just pay attention to CM.

Any ideas?

Definitely gonna BD tonight in case!!! Pic of my cycle now!!