Weight loss but it’s bad

Hi, I’m 18 and I’ve been having problems trying to gain weight. I’ve always been underweight, I don’t have an eating disorder; it’s quite the opposite. I can eat when I’m stressed or I’ll get nauseous and throw up. I can’t even touch it or I’ll gag and I don’t know why. I’ve been smoking to get the “munchies” and try to make myself hungry- but it’s not working. I’ve never been bulimic or had any other issues so I don’t know what’s wrong with me, I can’t even go to the doctor right now due to the virus. When I came home from college I was 102-103 and I’ve dropped down to 94. Obviously it’s not normal for someone who’s 5’2.

Any help would be great, I’m desperately trying anything at this point- and I appreciate if anyone can give me a direction on this.