How important is it to keep those promises? Will a bolt of lightning come down from the sky if we break our deal?
I honestly believe that God knows us better than we know ourselves. I don't think he expects us to keep wild promises that he knows are beyond our nature or our means. I think he hopes we will keep reasonable promises if they will better our spiritual lives and even, at times, our physical lives. If we read the Old Testament, there were many times God's chosen people did not keep promises, yet he forgave them again and again.
I believe that we need to try to resist making impossible promises, to keep from stressing too much when we can't keep them. And, I believe we need to try to make more reasonable promises. More than that, I don't think God expects us to promise him anything when we need his help.
He has promised us, many times, that he will answer our prayers, and he has not asked anything in return. The only thing he has ever asked is that we keep his Commandments, and especially the one about "Love one another as I have loved you."
Dear God, help me to remember that you have promised to help us when we need you, and help me to keep your Commandments, all of them, to the best of my ability.