I'm really confused about this cycle! Help?!?

[KatieA]

Hey everyone! New to posting here but have stalked the forum! This is our 3rd month ttc. I have had a 27 day cycle since tracking (to the day) Im using the Clue app to track and the estimated ovulation is CD 15. I started using OPKs this month and had a very faint line on CD 15 and 16. CD17 (I believe) I had a dark line, but not as thick as the control. At the time I wasn't sure if that counted as a positive or not. I figured not so didn't even track it. (We baby danced anyway) CD 18 the line was faint again so I gave up and thought maybe I had just missed it this month. A little back story. On the clue app, it suggests a 28 day cycle, but I always start the day before it predicts AF. So I thought maybe I o'ed on CD14. Anyway. Fast forward. None of my normal PMS symptoms show up. I typically have tender breasts close to AF so I take a test on CD26 negative. I got really crampy on CD 27 and figured the witch was rearing her ugly head. Nothing. No cramps on 28 and negative HPT (dollar store cheapy) Now here I am CD 30 very slight breast tenderness in my right only. Weird feeling in lower belly that I can only describe as active. Almost a tenderness but very far from normal pms feelings. Slight cramps on my right side but they are mild. I DID have a sharp stinging pain in my left lower back. It only lasted for 30 minutes or so but I had to lay down. I did have had several waves of light headed spells, and hunger like crazy. (I've been eating healthy for the last 6ish months and have lost a lot of weight since watching what I eat, my meals typically are satisfying for the day. But I've been having hunger pangs 2 hours after I eat) anyway I am PROBABLY symptom spotting especially with a "late" period, but would love to hear any thoughts. If I did ovulate when the OPK was dark what could the cramps from CD27 be?