Help me, please!

Let me start by saying I am breastfeeding but not exclusively due to my daughter failing to gain weight. So I’ve been using at home pregnancy tests and taking them like they’re candy... I’ve also been taking ovulation predictor kits. I haven’t gotten positives for either test which is fine. I’m 6 months postpartum so it’s been busy. I am trying to figure out what is going on. I have been cramping on both sides on and off. Generally with some cramping I will get my period within a day or two. This has been at least a week of the on and off cramping but nothing is happening. I wouldn’t say the cramping is horribly painful, it’s light, pinchy and pully. It feels kind of how it felt when I was pregnant with my daughter. It is a complete possibility because we have decided to not use contraceptives due to us needing fertility treatment to get pregnant the first time. We generally use the pullout method but have missed using it twice July 7th we missed the pull out method and Sunday or Monday (15th or 16th) my husband didn’t pull out. Again, I am also breastfeeding, not exclusively, though. Has anyone had experience with this? When should I seek professional help? I don’t want to be a hypochondriac and go see the gyno and have nothing wrong. Help please!!