Possessed? Almost certainly not.
Two recommendations - the first a couple of good books that helped me a lot in many areas of my life. They are not by a Catholic author so others may warn you off. Basically they are based on who we are, our identities in Christ, and learning to live according to who God says we are, and learning to believe that we are who God says we are. It’s sort of a Christian version of Cognitive Behavioural techniques and is great. The books are by Dr. Neil Anderson and are “The Bondage Breaker” and “Victory Over the Darkness”. He basically believes in what he calls “Truth Encounters” - when dark or false thoughts arise, challenge them by positively thinking or speaking the truth as God has revealed it. The books are not a cure-all, they take a lot of hard work, but the ideas are good (unless you read the anti-Anderson web sites). Here’s part of who we are in Christ:
ficm.org/whoiam.htm
There are probably similar Catholic books around - but I’m only just in RCIA so I don’t know them. There are similar non-Catholic books too but those are the ones that helped me a lot and some of the books are pretty poor. Actually - reading up on Cognitive Behavioural Techniques is recommended too for retraining patterns of thought.
Second recommendation - don’t fight temptation if possible. Instead, flee. When you say you cannot get yourself to pray during temptation this is false. By force of habit and repeated thinking it you may believe you cannot get yourself to pray at these times. In fact you can pray at these times. But getting over the firm belief that “I can’t do it” and actually doing it will take determination. I’ve been in that situation - not necessarily the same temptations - but the situation of believing “I cannot pray” at such times. It is hard work breaking out of it. You CAN pray at these times. That’s the truth. Believing it may be hard to do but it is the truth. (unless dissociation is a problem for you?)
Fleeing - don’t fight temptation by a mental struggle against tempation. You will lose. We all lose that one eventually. Fight by prayer, by going over your identity in Christ, by having a Bible on you at all times and reading it at the first sign of temptation (Read “The Way of The Pilgrim” for that idea - and others). I’m sure other people have much better ideas than me here. Get a little wooden box, fill it with good things - photos, writings, scripture etc. When temptation comes, open the box. Hard to do but it gets easier.
Fleeing - if temptation comes through reading things, don’t read. If it comes by watching things, don’t ever watch (easier said than done I know especially with the sort of things on free-to-air channels in the evenings these days). If it comes by thoughts coming into your head and being entertained, that’s harder - you can’t just throw your brain away like you can a book.
…continued (sorry about the length of this!)