Bummed!

I have such a regular period that when I didn't get my period I thought for sure I could be pregnant. Was feeling crampy, nausea and exhausted with back pains. All my pregnancy tests came up error so went to the doctor but not pregnant ?. Feeling super bummed and now struggling because I don't want this month to be wasted not trying. But it's so hard to know when I'm ovulating without my period this month.