If anyone says to this mountain, "go throw yourself into the sea" and doesn't DOUBT in their heart but BELIEVES what they've said will happen then it will be done for them. Therefore I tell you whatever you ask for in prayer believe that you've already received it and it will be yours-Mark 11:23&24 NIV.
If you're praying to God whom you seriously have doubts in then why are you praying? Things that make one say hmm! It's obvious that you haven't been taught Ephesians 3:20 NIV (He, who is able to do IMMEASURABLY more than all we could ask or even imagine); Genesis 18:14 NIV (Is anything to hard for God) & or Matthew 19:26 NIV (With God all things are possible).
I've got another question for you. If you've already prayed about it then why are you still worrying about it? Worrying is just another form of doubting! In Luke 13:25 NIV the Bible challenges us by asking who of us by worrying can add a single hour to our lives? Then it goes on to say in verse 26 since you can't do this very simple thing, then why do worry about everything else? Something else to make you say hmm.
If you feel skeptical or apprehensive, which essential means to doubt while you're making your request known (Philippians 4:6 NIV) then maybe it's time for you to reevaluate who God really is and most importantly what He's capable of doing.
Our God is an awesome God remember that when you're praying about whatever!