PCOS and chronic depression here. I'm not as thin as you but have never been close to being overweight. Highest I've been is a size 6. I'm hungry all the time and when I'm depressed I don't give a shit about what I eat. But I've realized something. My not giving a shit eating and a planet's not giving a shit eating are 2 entirely different things. I don't just sit and eat bag after bag of chips, eat an entire pizza, drink a 2 liter bottle of soda and go to Wendy's. I'll eat some homemade cookies. Like 5 of them, and the rest of my food is more or less the same. So thankfully my weight doesn't fluctuate much from my depression unless I get really depressed in which case I'll lose 10 pounds.