Ovulation cramps

Hi ladies, so I'm looking for some advice 😊 i was due to take the pill Tuesday 5th (we agreed i would come off it for a baby so i didn't take it and haven't since.), I started my period Friday 8th. I have no idea what my cycle is but on a guess I'd say 28 days. Therefore i am due to ovulate tomorrow... This is our firrst TTC and its only been 2 weeks but we have had sex loads!! 🙈 i have really bad cramps in my lower tummy.. The internet says it could be due to fertilisation... Is it possible to conceive before i ovulate? Unless my ovulaion date is wrong.. It was a rough guess... I never get cramps unless I'm on my period... Plus the ovulation test is negative... I feel its too early to be pregnant.. Have any of you ever got cramps so early on and it turns out to be because your pregnant? This is all so new 🙈 xx