Question about OPK's

So I've been using OPK's to try and detect my LH surge and they keep coming up negative even though CM is EW (or getting there for sure) and I feel my usual cramps and certainly timing I should be getting close to ovulating. So I'm wondering if anyone ever had a similar experience with OPK's and them always coming up negative. Even the last couple of cycles of me checking the line was present for a couple days but always much lighter than the control line which according to the directions means it would be negative. I make sure to check 3-4 times/day and have concentrated urine. Is it possible I'm not ovulating at all and it's just in my head that I think I am?
A bit of back story here-- I'm still bf'g my 18mth old but only a few times a day and never during the night (he sleeps through from 8pm-8am) and only got PPAF back 3 cycles ago. I do think my body responds well to hormonal fluctuations protecting me from getting pregnant so I really think breastfeeding worked well for birth control for me. Another example of this is when I was on the mini pill with my 1st son and although they say it's only 90% effective (or something like that) and you have to take it at the same time every day I could easily miss a day (which I was known to do) and after going off of it it still took 3 months to get AF back. It's so annoying!
I have a notoriously long cycle, always have I think… at least 37 days sometimes a bit longer (which is great when not trying to get pregnant)! Even after I was diagnosed with hypothyroid and on synthroid it never changed my cycle length one bit. BTW, my TSH levels are great and was recently checked and within normal limits.
I also run 5 days/week 60mins a day but I'm average size (135ish lbs and 5'4) so despite my exercise regimen I definitely am not too small and eating more than enough calories to keep up with that. I eat a lot of carbs which is why I think I'm not losing a ton of weight… I just can't seem to cut out bread. lol
I was taking vitex for several months which might have greatly contributed to finally getting PPAF back but stopped taking it this month just to see what happened. Initially I was taking it 2-3 times a day for the whole month but dropped off to just 2wks on/off after atomic made that suggestion.
I'm not temping because I don't want to get too crazy about trying to conceive even though I'm 37 and obviously time isn't on my side. It's not a huge deal to me if it takes several months to get pregnant but I definitely want another child so trying to figure out my body again, kwim? Also, there is this terrible feeling that I have that if I do too much to sway that I'm somehow jinxing myself and will never get a girl which is my desired gender because I already have 2 beautiful boys! That's just the way my life seems to work… try too hard for something and it doesn't work out so I'm trying to stay relaxed.

Sorry this is so longwinded I was just trying to give the best picture possible of my situation. I hope it's not confusing?!
Thanks so much for reading!

37 days is not that long a cycle.

If you're getting AF, the odds are all but 100% you're ovulating.

My advice would be (and is for anyone who doesn't get clear pos OPK) is to drop em and start the every 4 day BD method. This is a new thing we've been trying with good results so far. Just BD unprotected, every 4 days, starting after AF and going thru the whole month if you aen't sure if you ovulated, or stopping after O (except for recreational purposes) if you do know when you O. This ensures you'll have one attempt in fertile window without having to worry about OPK or tracking cycles. May take a couple months but it wil happen!

Thanks Atomic for getting back to me so quickly! I think I'll take your advice!

I've never had a positive OPK with any brand. I have regular cycles and have had O confirmed by bloodwork/ultrasound/pregnancy in cycles where I tested multiple times daily with OPKs. With Wondfo OPKs I get an almost positive line and I just consider that my positive. But I also have a short surge and sometimes O within a few hours of my darkest OPK so even Wondfos don't give me much warning always. Based on temps, CM and CP and years of charting I use those signs to determine O and I do the BD every 4 days.

Good luck!