What would really help is seeing what your shots look like. I don't think a member can upload to the gallery until he/she has 5 posts, however, I think you can add an attachment to your posts here in the forums.
Understand, too, that Programmed Auto mode (P) is essentially full Auto with the ability to alter the f-stop/shutter speed combination in a way that results in the same exposure. (e.g., one f-stop open and one shutter speed increment faster.)
Point of focus shouldn't affect exposure, but metering will. Again, we'd need to see your subject to help fix the problem.
Welcome to the forum - you'll get lots of help here.