Delivery/c-section related??

So I'm 4 weeks pp and curious if what I'm feeling is related to my recovery. The past few days I've been feeling really icky! throughout the day I'm not as bad, but at night I'll be freezing, then I wake up drenched in sweat, like I'm fighting off a fever. And I keep getting these really bad pains in my loser abdomen and back. Almost like contractions or really bad cramps. I just had my postpartum visit with my ob and she said everything looked great with my incision and cleared me for physical activity. I hadn't started feeling too bad until after my visit, so i didn't think to bring it up. Another thing, I did have some drainage in my incision a few days ago. Before it drained, it swelled up and was more painful. But it felt better after, and my doctor said that it was completely normal, and I'd be fine. Anyone have any similar issues during their recovery? And if not, anyone have ave idea what could be wrong with me? I've never felt like this before.