In that case, because you are a Christian, you are not demon-possessed, but, you are probably demon oppressed. This means the demon is not in your spirit (a Christian’s spirit cannot be possessed by demons because the Holy Spirit is in a person’s spirit), but it is in your soul or at least it is oppressing you from outside of you.
However, because your friend dreamed that she is casting it out of you, the demon is probably in your soul.
You will have to find someone that can cast it out for you (when a demon is in a Christian’s soul, it has to be driven out just as it has to be cast out of the spirit of an unsaved person). When demons are oppressing people from the outside, they have to be driven “away” from people (not out of people).
Anyway, you will always struggle with lust if you don’t make a plan with this issue as I suggested.
The second dream is interesting, it appears that after you have been set free, you will be able to help others with the same problem. It appears that you will be able to cast demons out of people. This is the only explanation that I have for the second dream.