I took this of the “staying pure” thread, I think it applies here.
Firstly understand that you are completely normal. There is a reason doing Teshuva exists, if no one would need it, what would be the point?
I once heard (I have no idea where) a very nice concept. Every person has a rope connecting them to Hashem. Every time a person sins, the rope breaks a little until eventually it breaks. When a person does Teshuva, the rope gets knotted. When a rope is knotted, its shorter than the original length.
(I hope this is making sense.)