CD20 and ovulation

I am on cycle day 20 and I am just starting to get faint lines on my opk(yesterday and this morning). Should I be nervous that it's so late? I felt tons of cramping yesterday afternoon, which is consistent with the ovulation pains, but the tests are saying otherwise...I know the line has to be equal or darker than the test line but it just felt like yesterday was the day...what symptoms do you feel with the LH surge and then also with ovulation? Thanks, first month ttc, and I'm so nervous.