I live in a hostel.. The person that was in my room also did some buddhist stuff, and we did have some trouble with some weird things. But we anointed the room and prayer for God to break any stronghold or bad thing and things sorted out after that.
Can Christians be cursed? Well how about you go practise some witchcraft stuff and see what happens

Even thought we are christians demons can still affect us if we open the door to them. But they do have limited access usually I guess. AFAIK demons can never get complete control over a christian but can only affect them. Like cause doubt and feare or depression.
But I think it's not a good idea to go shouting demon! demon! all the time.
But it's also a bad idea to be ignorant of the schemes of the devil.
George if you think something is wrong.. Pray! God gave you all the authority to break every curse and stronghold that might be placed over you. Also ask your Pastor to pray for you or a cell leader or close friend. Then praise God that we are made free of the oppressions of the devil

I suggest finding another doctor maybe?