Having trouble eating and gaining weight!

So for about a year and a half now my appetite has been struggling. I’ve become extremely depressed and stopped eating like I used to. I’m struggling to put on weight and my weight tends to fluctuate like crazy. I’m 19 5’7 and i usually fluctuate around 104 to 108 lbs. I’ve tried protein powder such as whey but that’s more so working out and I haven’t had the energy to workout because of how little I eat. I’ve thought about trying ensure shakes but it can be quite expensive.

I just need some tips to try because my health is really bad. I can barely get out of bed, my hair is falling out, I have no energy to do the simplest things, I’ve been getting migraines everyday and maybe it doesn’t have to do with how little I eat but I feel like it is a big factor.

Just to give you a rough estimate i probably eat about 300 calories a day some days I can eat dinner but a lot of times I work nights so I come home around 9:30 and im extremely tired and out of energy to even prepare anything and I do live on my own so it’s difficult to keep up.

I just want to feel good about myself. I feel like death all the time. I just want to have energy like I used to I can’t keep living like this and especially in quarantine all I do is sleep and work