If you just keep making yourself believe, it is like pumping air into a balloon to keep it full, while always running around patching up the holes. The problem is actually that the balloon you are inflating is not solid, because it keeps getting holes. Rather, what you should do is investigate why your balloon is not made of a quality membrane. Using this analogy, a quality balloon (let's say, the truth) will not develop holes, and it will not pop under pressure. The only way a quality balloon can deflate, is if the air that has been pumped into it is sucked out of it.
I recognise that the balloon you have (the basis of your faith), must be somewhat of an imitation of the real thing (no offence intended, it's just a tip). Therefore, I suggest that for you to have a solid faith that has natural, self-sustaining belief, you need to identify how to place your faith on the rock of truth. It seems to me that your experience in Christianity is like all of us who grew up within it and adopted it as a given without having really questioned it: probably you have come to understand the promises etc of the eternal consequences of Christian faith, but seeing as have been afraid to courageously question what we have believed, not really come to a self-discovered understanding of the real political story of Jesus, the kingdom of God on earth, the various powers that challenge/covet it, and why Christians are called to be faithful. Once you understand how serious the situation is and that God's people are required to cooperate with and serve Him obediently; that an innocent man was not trusted and accepted for being totally honest and good, but was slandered, wrongly accused, and brutally eliminated because He spoke unwelcome truths.. probably you will accept the calling to serve Him.
That basis of faith will result in the real, sincere belief of what you have actually realized is true, and you would never again have this cause to doubt. I do not really think that blaming any mental problems (anxiety, OCD) will help you to get the solution. I do believe that seeking and obtaining the right understanding of what Christianity is about will inspire you to have faith, and that will give you the solution. Furthermore, exercising a good relationship with God will enable Him to teach you how to manage anxiety, so that you will become more peaceful and calm, as these are the resulting fruits of a person who trusts in Him and learns to live His way.