Strange feeling help!

Danielle • 11 days late for AF, feeling anxious!
Tmi but last night during sex for the first time I was really tight all the way through, at some points was struggling, was quite painful. It was as if my walls have swelled. I've been feeling sick and tired for last 2 days. Due for AF on the 30th, already ovulated while having pleanty of ibtercourse. Any advice please? Great full