If you're weak in faith it's because you're weak in the Word! The best cure of doubts is the Word! The Bible says, "Faith cometh by hearing the Word of God!" (Rom.10:17)--That's the law of faith. So if you feel like, "Oh, my God, I just don't have enough faith!"--it's because you don't have the Word.--Because faith comes from the Word! Faith comes, it grows by hearing the Word of God. It's not a sudden boom. It is something that is built by faithful study of God's Word.
He even gives you faith to believe His Word. He is the "Author and finisher of our faith." (Heb.12:2) Faith isn't something you work up, muster up or polish up by your own efforts and strength! Accepting faith through His Word is a work of God's grace. The only thing you have to do is receive it.
So please do not neglect His Word! It is food for your soul and gives you strength for the battle! It is His Word by His Spirit in His Love that makes you strong! Lord help us to stay in the Word of God, grounded in the Word of God. It's the Word that will increase your faith. Faith is built on the Word! So read it prayerfully and ask God to increase your faith, and He will!--He never fails! He'll always answer the hungry heart! God bless you and help you to find faith!