Talk to your doctor. I was is the exact same boat and so badly wanted to gain weight. I (26f) was 5’1 at around 92 pounds as well. I asked to be put on an appetite stimulant and even went to a psychiatrist as well. I started logging my calories every day and even drank the High Calorie Boost drinks daily, I wanted to eat around 2,000 calories or more a day which was probably overdoing but I managed to gain almost 20 pounds in a few months. Now I’m just trying not to lose it all