Hearing God's voice

I would just like to know how one can be 100% sure when you are hearing God's voice. Most of the time I am pretty sure but sometimes I am afraid that I am making up stuff or something and then I am afraid that if I don't act on what I think I am hearing, I am being disobedient but I don't feel entirely confident that I am hearing correctly either. We don't have many prophetic people in our church - only one that I know of - so I cannot get much training or mentoring there. Our pastor does not have a problem with prophetic stuff and so on, but doesn't openly encourage it either. I do have an accountability relationship with the other prophetic lady in our church and with the pastor, but I believe I am hearing God alot on a daily basis and I want to be sure that I am hearing correctly. I can't share everything every day with someone but I am desperately afraid of going into error without proper training. I know I am in the right church for me at this time, but I am not going to get much training there. What is one to do in this sort of situation? The prophetic calling is not going to go away and I don't want it to anyway, but I can't really move ahead without any interaction with other prophets. Pretty new at all this stuff (been having dreams and visions, etc for years but never actually did anything with it before).