How did you feel at 11 weeks post partum?

I'm 11 weeks post partum and exclusively breastfeeding. I'm 23 years old and my husband and I love love LOVE our little boy. We have been using protection but at my 6-7 week mark we did have unprotected sex a few times since it was our anniversary weekend and we got carried away (I know you can get pregnant even if you're breastfeeding). For the last week and a half I've been experiencing sudden nausea (usually after I eat), one day I had endless cramping, and I've been very dizzy sometimes despite drinking enough water. My nipples are now very sore (never had any problems breastfeeding so far) and my baby has been oddly fussy at the breast at times. Today I had a large amount of cervical mucus that was extremely milky and not stretchy or watery. And after having lunch with a friend I came home exhausted and instantly fell asleep for two hours. My baby only woke up once last night I am not that tired!

I've taken so many tests this week and they're all negative. I feel like I'm going crazy, can anyone shed some light on my situation?

I wouldn't be posting if I weren't desperate for a fresh perspective 🙊