Last night I masturbated to a disgusting sexual fantasy for the first time in weeks

I went through a rough patch last year and started masturbating to disturbing fantasies to cope with the stress. Most of my teenage years I looked at porn and masturbated to an excessive amount. I stopped looking at porn and masturbating much for a year or so, because some of the psych meds inhibited that sort of behavior. I ended up in the hospital because I was self harming. They put me on some different meds. When they mentioned it had no sexual side effects something in my head told me this wasn't going to end well. I forwent my old habit of pornography for fantasy and things got out of hand again. I started fantasizing a lot of the time as a way to get away from stress. I feel bad becasue of their content, I know thoughts are thoughts, but it still bothers me. I would stop thinking about them for a couple days but I would start to feel overwhelmed and lonely strangely. I suppose they became a replacement for the idea of relationships that overwhelmed me. I tried looking at pornography again and it actually aroused me more than the fantasies, but lacked the emotional component, even so I had trouble stopping. Up until last night I went weeks without masturbating to these, but I've been really depressed of late and it improves my mood. I feel ashamed of these ideas and I quite loathe myself for them, but I'm too scared of relationships and sex to think of anything else.