Hi and welcome to NeuroTalk!
Unfortunately, fatigue seems to be one of the side effects of the Interferons. I was on Beta for a long while before I just couldn't tolerate feeling sicker with it than I did without it.
If fatigue is already an issue for you without the DMD it's probably going to continue to be your main sx.
Have you tried one of the meds they have for fatigue? I used Provigil and it worked very well for me. I don't take it any longer because I don't take any of the Interferons but it was very effective for me when I took it.
Hope you feel better soon!