Is there any way to correct this easily? The base of the house is slanted.
Yes, some screenshots would be ideal. If slanted is the problem it probably is easy to correct, but what we always say it that it's super helpful to start over if you feel you have accumulated too many errors. It is always always a good idea to start over, there's only benefits.
Yeah I thought the images posted. Yeah true, I'll probably start over.
Well, you are only in the block out stage. The purpose of this stage is to have a rough idea of the proportions of the actual model.
It really isn't important at this stage.
However, your OCD in perfection will be to your advantage in producing awesome models in the future, although may hinder progress early on.
Modelers OCD is a requirement to succeed, we all have it.
Yeah, just start over. But by the screenshot it looks like you are having trouble navigating the 3D viewport more than anything. When you start is hard to get the feel of 3D space. Perhaps consider starting with the Basics course and Fundamentals. Linking you up:
https://cgcookie.com/courses/blender-basics-an-introduction-to-blender-4-x
https://cgcookie.com/courses/fundamentals-of-3d-mesh-modeling-in-blender