Now . . . I know it is not absolutely necessary to HAVE to have an exorcism to be rid of even severe demonic influence and infestation. There was a time when I myself was quite "oppressed" because of putting myself into dangerous spiritual situations . . . and "they" had a serious, vice-like grip on me. Any time I would attempt to make a break . . . "they" might back off for a time, luring me into a sense of false liberation, but eventually I'd find myself bound up and under "their" thumb even worse than before (as per the scriptural warning--Matt. 12:43-45) . . . because if you are trying to expunge evil presence through self-effort, self-will and it's not happening through Holy Spiritual regeneration, your soul is simply a vacancy ready for demonic re-habitation. . . .
But, aside from direct intervention from a qualified Biblical intercessor who casts out the demons, the Lord Himself can and may arrive personally to do the work through the Holy Spirit. I was alone when it happened to me. I was battling alone and not in any fellowship with Believers at the time. Far from it. Yet, the Spirit Himself came and ministered to me--first in a big, glaring way, which left me with no doubt that divine intervention had occurred, and then, off and on over a period of a few months . . . culminating in a clear vision where I "saw" that Jesus is indeed THE Lord of all and the ONLY way to the Father. . . . "The Way and the Truth and the Life"!
It did not matter that many times before I had grown angry at God for not coming to me when I asked--BEGGED the He show me the Way. And that after some of those times, in frustration and brewing resentment and fatigue in seeking . . . I had actually abandoned myself to the "prince" of the "world", because it seemed that at least HE wanted to take me places (where God just seemed silent and indifferent). . . . Nevertheless, even after such dangerous dabblings and giving up on seeking Him . . . God still did finally come crashing in to my rescue and delivered me from severe bondage.
Which all goes to say, please . . . do not give up hope. Even if you have or continue to give up hope! I believe that those who are lost for good--who are not EVER going to be one of God's "children"--do not show signs of caring. They do not battle and fight and continue to strive to be saved. The fact they you are still going to the wells of truth--that you admit to the suffering for NOT being in a good position with respect to relationship with the Lord . . . tends to show to me that . . . you are His after all. The "perfectly possessed" are quite at ease (in a sense) with their lot. They don't seek God. They don't care that they don't have the "peace that passes understanding". They are relatively (to utterly) content in their service to the lord of this world and of darkness. They have no interest in going to or engaging with Believers, unless it is on a mission to destroy, disrupt, undermine. They have no interest in learning and in gaining understanding of the truth and of light. . . . Unless it is to spy or to cause harm, they cannot bear, for instance, to come to a place like this where the glory of God is written of continuously. This kind of writing is like nails on chalkboard to them. They're are either disgusted or frightened by it and only see it as something "fanatical", "extreme", "kooky" etc.
But hear this: In the end, if you are His . . . there will be nothing that you can do to thwart Him eventually coming to get you. . . .