Ovulation & cervix?

got af on march 11th & april 11th. then may 6th. i have been using the opk (strips) since cycle day 9 and the lines have been really faint where i barely can see it. so i have no idea why its not getting dark. last month when i used teh strips i got a positive on day 13. but nwo this month i still havent gotten a positive and today im on cycle day 13. today when i tested i didnt get not even a faint line. i have small cramps. and i had alot of white sticky kind of water cm but its not the type where it stretches between yoru fingers . i never have that type of mucus. do u think i missed my ov date and just start trying to test again next month or should i keep testing? i bd on wed .may 14th,18,19,& today (20th) but last night i noticed when i was on top it really hurt up there inside. felt different from before. i ran out of ov strips but i know i didnt miss my ov date i just have to try to pin point it on teh days comin up or if i was lucky enough to catch it one of these days.