Clicked through the thread quickly, and it does look like you thinned out some between the pics in the middle of the thread, and untill now. I also picked up that you were off treatments for a little while (correct me if im wrong). Anyway, if your back on treatments you should have a good chance to recover, the only problem is that it will take longer for the recovered hair to look good with dreads (shedding, starting new cycle, new hair growing long takes longer with dreads etc). Another thing about dreads and hairloss, is that your hair will seem thinner and heavyer because the roots arent as solid as they used to, and your locks will hang down like theyre glued to you cheeks.
I had dreads for 3 years myself, and this was the period where my hair thinned out. I figured that hairloss and dreads was a bad combo, so i cut them off, hoping that my hairloss was related to traction alopecia and that it would grow back after cutting. I waited a year to see if any of the hair would regrow, but it didnt, and then i started treatments. At the time i cut my hair, it was MUCH thinner that yours right now. And believe me, it was a pain showing it off to everyone...
Give it a little while and see if it gets better, but you should consider cutting your hair if it doesen't (i know it will be hard). How is your treatment timeline btw?