Rapid weight gain - so confused

I’ve always been fairly small - tall and slender. I gained 26 pounds during pregnancy but lost it all within a couple weeks of having my child BUT now I’ve gained it alllll back and then some - most within a couple months. I’m talking rapid weight gain - 2-3 pounds every 1-2 weeks. All the while I’m hardly eating anything! Hormones specialist claims my estrogen is too high and adrenals are wore down so put me on meds. Has anyone else gained so quickly? Ps my thyroid is normal! So discouraged I’ve never gained so quickly. An example is this week I may gain 181 but by the end of next week I’ll be 183 or so. So discouraging especially while watching my food and eating healthy. No I don’t exercise but I haven’t in a long time - nothing new