Still no positive opk

Nathalie
Hi, it's my 1st Month using glow
​ 
​I've been taking OPK since CD12 and I'm on CD21 now. My previous cycle was 32 days, 31 before that and 33 before that. 
​I haven't had a positive OPK yet. Started with one each day, but switched to 2 after two days of testing.  This is our 1st month using the tests (tried without first).
Based on my previous cycles, I should have o'd already, shouldn't I?
​I'm experiencing cramps, but not like before (feels different and much longer).
​I did have trouble DTD on Jan 30 (painful) but I was already testing by then.
​ 
​Going crazy! Don't know what's going on! What's do you guys think?