Faint positive pregnancy tests?!!?

We have been trying to conceive #2 for some time now. My period is one day late. We never got a strong positive result on our OPK(ovulation) tests. But we baby danced anyway in case i had a short surge and missed it. I am not temping so I cant confirm EXACTLY when i ovulated. But i have cycles that are every 28 days like clockwork. I took early result pregnancy tests on on 9 dpo(days past ovulation), 10 dpo, 11 dpo, 12 dpo( hey i am a poas addict, lol) all of which were negative. When i tested this morning, once i saw my period didnt come yesterday, all three were FAIIINTLY positive within the first three min of testing. And the tests were even the REAL sensitive ones. Has anyone heard of a faint BFP(positive test) that late? We will be seeing a doctor early next week, but I hope that such a late BFP isnt cause of worry or sign of a chemical pregnancy. Any input? we are VERY excited, but dont wanna gt our hopes up. DD's pregnancy test was blaring positive when i was pregnant with her