I have never experienced what you mention Grouchy,but I do believe what you say.If you dont mind me saying,I think you are right in recognising its evil,and hope you stay away from that situation :(
Yes using Ouija boards is a avenue to demonic possession. Do you still feel you are affected?
Well demons can be removed from people by those given that ability by God. I was encouraged to answer your question because you proclaimed them to be """ But I know its bad, its just bad.""" So I would encourage you to talk to God and admit your error and seek His intervention in this.
anger and resentment are evil to! I forgave my father long ago... : )