In my experience, that means you have unresolved issues. You are angry with yourself or have a lot of buried fear.
I experienced something similar for some time when I first started out and it never totally went away because I'm a generally miserable person who's issue that manifests it persists.
But you know what I found helped? Learning to accept myself and what I am, and work on to change that of myself that is destructive to myself and others. I continually found this to be the answer presented to me in my conversations with Satanic entities.
If you haven't already, I would strongly suggest you don't dive into any magical working as you need to find the source of your conflict before you can safely go forward. Take it from me as someone who didn't, you will be much better off if you go the safer route.
If you have, I'd suggest you pull out and ground yourself back to reality. Take a little break, then try to address your problems rationally and critically. Work out what it is inside of you that's allowed you to manifest these nightmares and work on that in your life. When you think you've at least not allowed it to control you, you can resume your magical practice.
Satanism is ultimately a path of self-empowerment and overcoming adversity through individualization and perseverance. So it's part of the process and you gotta approach it with sincerity and not try to rush things too fast if it gets really intense or negative like you described. In my own experience trying to do that will burn you out for a while and delay progress.
It's time to face your Shadow. (This is why you use Baphomet on your altar--to access your Shadow.)
Shadow (psychology) - Wikipedia
By the sounds of it, I can't say he is ready
yet. I would urge caution as doing something prematurely can have pretty bad effects on mental health. Neither of us know him personally well enough based on his posts to be the judge of what kind of person he is or if he is ready. This can be dangerous territory especially if there is any mental illness known or not with the practitioner. What I do know of the poster, based on what they have said before, is that they are fairly new to Satanism.
I mean, this is Satanism we are talking about. It's not exactly something you just go off and do without preparation. Okay, maybe people often do, but that doesn't mean it's wise. This is potent stuff, you know?