Presious Sir, may I give you some practical advice.
Be leary of any "expert" who claims to be able to help with demonic issues but wants money to do it. These people are just out to take advantage of you and steal your money. No one who is empowered by God and has a personal relationship with him would demand or require money. Legitimate people in spiritual warfare ministry would be willing to help you WITHOUT a money attachment.
Read God's word and memorize it. Use it to renew your mind. When negative, evil ideas come or voices come into your mind, cast it down by speaking scripture in faith. Repeat it in your head, say it out loud, post it around your place, and get pre-recorded scriputure to play. Constantly listen to it when at home, in the car, ect..... The devil hates the truth!
Pray to God in faith. He promised to empower believers with the Holy Spirit to overcome the works of the devil. God can give you the power to drive this thing out of your life.
If you are into sin stop! You are just giving the devil a foothold to enter your life and allowing him to build a stronghold. Confess all sin and repent. Have you or your family ever been involved in any type of occult activities? (ie; channeling, taro cards, satanism, weegie boards, black magic, spell casting, clairvoyance, palm reading, necromancy, astrology, voodoo, witch craft ect... .)
These and many more pagan dark arts are strictly forbiden in the Bible. If you or your family are involved(or have history) in any of this stuff the devil has an open door to attack you. He can gain control over you(or parts of your life) much like a hacker can gain control over a computer when the firewall has been breached. If this is your situation you will need some serious spiritual intervention.
Remember, even the devil has limits. He can only go as far as we will permit him. Resist the devil and he will flee from you.
Find a Bible Based, Spirit Filled Church! Bring your need to the Senior Pastor. Ask them to pray for you. They may be able to refer you to a real expert in this area. They should be more then happy to help or point you in the right direction.
If you put all this into practice and nothing seems to be changing, then you may also want to seek medical advice as there could be a legitimate Mental Health issue. I would check with the V.A. to see what they can offer you if you need to explore this option. Being a vertern of such a horrible war there may be unresolve issues of Post-Trematic Stress. There could be history of family mental illness.
God Bless you! I will interseed to God for your situation and take your situation to my local church for pray.
Remember that God loves you and wants you to see you free and whole. He will not give up on you.