I saw my therapist yesterday and he said I'm fine and to keep telling myself that this will pass. But how long will it take before I believe him
Psychologists don't have any answers -- they just have questions. The theory is that the answers are inside you and the therapist is there to open you up to them. It may be hooey, but it works for some, and not for others. But if you were making progress I wouldn't be too worried that you hit a snag -- keep working. But if your psychologist runs out of things to try, then you need a new one who has more tools in the kit.
I do the homework but I get frustrated when I don't get relief. Shouldn't he be more supported and not say I have no answer. I don't want to change therapist
Are you fully putting into practice the strategies your therapist has suggested, and doing the "homework" he/she has given you? If so and it's not helping, you might consider seeing a new therapist in order to have a fresh and objective viewpoint and hopefully get back on track to recovery.