Cramping 8 weeks PP

Hey mommas, I’m 8 weeks PP. I been feeling cramping quite frequently in my lower abdomen. It does not feel like my normal menstruales cramps. I also feel it in my lower back. I did have spotting about a week or two ago with cramping after sex that lasted a few days surprisingly. I also been feeling a bit nauseous at times. I also been experiencing a bit of lightheness as well, mostly while standing. My cramps feel worse when I stand too.. I’m not pregnant again. I never used to experience this before. Is this something I should get checked? What could it be? And is it normal postpartum?

I am breastfeeding.