Why have I began having sleep paralysis?

Back in September I had a drug induced panic attack, it may have even been a partial seizure i'm not entire sure what had happened. Afterward I suffered about 2-3 months of severe anxiety which was what I ume to be subconscious because I personally didn't feel anxious over anything. Though I could tell something was wrong. Those symptoms have almost entirely disappeared, and since they have gone, my sleep paralysis episodes had begun. I'm not sure what causes them, I don't see supernatural entities or experience anything other than pure paralysis. It usually occurs when waking from a bad dream or a strange dream. I find myself unable to move, but completely in control of my thoughts. Sometimes I see myself move, but then i crack my eye open to realize I haven't moved at all. In one scenario I even stood up and was wondering why I still felt paralyzed even though I was moving, which turned out to be a dream which I woke up from after a couple seconds. It happens infrequently, maybe once or twice a week and usually lasts no longer than 5 seconds. My quest is, what could be causing this? Some deep rooted anxiety? How can anxiety cause this? Or did the drug mess up part of my brain? Also since then I sleep uncomfortably on a couch every day and have an awkward sleep schedule because I had to move, not sure if that can affect it either. Any responses are appreciated :)