Is masturbation permissible if marriage is not likely to occur?

I am a young person female who have muscular dystrophy which means I can't move my body and 90% depending on everything wheelchair bound. So my problem is that I have started get feeling sexual and I know that I won't be getting married to anyone due time illness and zina is a big sin and there is no option for that. But the feelings are getting stronger for me day by day, I have read that those who can't afford to get married should fast by hadith but I can't even do that due to my genetic disease also Masturbation in Islam is forbidden then what should I do I am getting very upset now a days & frustrated