Hi. I know how you feel too. I have months of feeling really low and then days when I think things are getting better only for it all to come crashing back down onto me again. The only difference is that I'm in my forties now and have been dealing with this for 20 years!
About 4 weeks ago I started cooking with coconut oil and putting it on my skin, taking vitamin D tablets and also taking L Glutamine once a day and shortly after I went through 10 days when I was massively better. I thought I'd found the cure, people started being friendly and not putting their fingers under their noses around me. This was the first time that I'd had any real noticeable improvement and I was so happy until one day it all returned, back to the same situation I've always been in.
Whatever it is we suffer from, it's proper cruel but all we can do is hope and try and stay optimistic. I hope we all succeed in our quests to find some kind of normality. Good luck to all!