But without faith it is impossible to please him: for he that cometh to God must believe that he is, and that he is a rewarder of them that diligently seek him (Hebrews 11:6, KJV)
One major cause of doubt is overanalyzing circumstances. By over thinking, people tend to seek for the reasons why faith will not work. They consider the wrong report and begin to exclude the sovereignty of God from their thinking. They forget what the Lord has said, and rely on human reasoning. Instead of following the principle of “God is,” they follow “God is not able.” Without realizing it, they put man ahead of God, hence having gods before Him. That is to say, they will take counsel with unbelieving people, and begin to doubt God’s abilities. While having counsel is good as a general principle, taking counsel with the wrong people is a bad idea.
Counsel should always begin with the Lord so that He can guide us through the Holy Spirit. In turn, the Holy Spirit may lead us to others, sometimes not. He knows exactly what we need and to whom we should listen. An oversimplification would be asking spiritual advice from a hardened atheist. There may be times the Lord may simply state the facts, give direction, and ask us to stand alone in the sense of not looking for confirmation from others. This is a relationship builder with Him, and a way to ground us in the Faith that always stands. Sometimes the Lord will confirm His Word quicker when we don’t look for the confirmation. True faith comes by hearing and hearing by the Word of God (see Romans 10:17). We need to hear His Word, not natural man’s counsel.
The Lord may indeed lead us to others to confirm His Word because His Word abides in them. He may use them to bring clarity, but He will not use them to bring doubtful disputations. A true counselor of God will not cause another to doubt God or His Word. He or she will always point to faith, not doubt or unbelief.
Another helpful blog to consider would be "Eliminating The 'What-ifs' (No More Emotional Stress)."