Confused with the test

Angela • 44 yr old Mother of 3 older children to previous marriage & a 4 year old boy to my partner of 5 yrs, ttc no 5 for 2 years, did fall pregnant last year in June but lost the baby at 12 weeks. Now Just had my baby boy Heath William 13/03/20 😍

I took a test Sunday afternoon cd 15, & was positive. I woke up at 3am Monday morning with bad cramps, thought I was going to get my period but didn't, never felt anything like it however I'm usually on the pill & this is my second month off it, so I'm not sure if it was ovulation pain? Next day took another & looks like it's lighter? Can someone help me understand it please