Unable to eat. Affecting my immunity?

Hi. I am unable to eat and gain weight. I used to weigh 100 kgs earlier before i lost my appetite. Now when i try to eat, my appetite has gone extremely down plus i feel i will vomit if i continue eating after a couple of bites. My health has gone down tremendously and i am still loosing weight every month mainly because i am not consuming enough calories because of this. Also i dont find the food to be as apealing and tasty as i used to find it earlier. So i dont feel like eating it all the more. Moreover, its been around a year since i have lost so much of weight after which i also got alopecia. I was wondering if alopecia might have started because of sudden weight loss affecting my immunity? PS: i have already tried breaking my meals and having it every two hours which didnt work out as i feel like vomitting when i start eating. Though i dont puke, but i just get that feeling when i eat food.