New to Glow, help please!

Today is CD 28 for me, on CD 23 I got a blazing positive OPK which is very rare for me. Yesterday and today I have felt nausea and dizziness (things I never do with AF) as well as a ‘ different’ cramp-ie feeling. I’ve have 2 pregnancies, first a miscarriage and second a beautiful baby girl. She’s now over 2 and we’ve been TTC for a year now. I’m not new to the game but I am new to getting a positive OPK. In all the time I have took them I’ve only gotten a positive 3 times. With my daughter I was the test for pregnancy even on my period type. I had it bad. If I am pregnant, could it show this early being as its only been 4 days since I got a positive OPK? Could it be possible the positive OPK was a dud? Countless nights I’ve laid awake reading forums of people asking these type questions. And I know even thought the only way to tell is time and test, it’s just a sense of relief to have someone give you hope. Please, respond gals!