Hormones out of wack a year and two months after giving birth.

Has anyone had any trouble with their hormones long after giving birth? I’ve had two children, and every single day I feel like crap. I am nauseous all the time, headaches everyday, breasts have been sore for about two months now, my last two periods have been weird and all symptoms point to pregnancy. I’ve taken idk how many tests, and all say not pregnant. Which I didn’t think I was to begin with, but I’m thinking I may have a hormone imbalance. I’ve scheduled a gyno visit for this week, and I’m just more concerned about them trying to put me on birth control instead of looking deeper into the problem. I’m not sure, but I was wondering if anyone out there has a problem just like mine and knows what it is.