Have you had a pause in your training? For that's one reason which will certainly get your picking in not so good condition only in a while.

And for the second question, I know EXACTLY what you mean. Had the same problem about a year ago, then I started taking lessons from my new(est) guitar teacher and he told me (I was playing both ways, or a mix up, low strings E,A,D with my hand "floating" above them but the high strings resting my hand to the lower strings) that I might want to try to rest my right hand on the guitar body when I play low strings and make a slight move to rest on the lower strings when I play the high notes..

I hope that's any help. Play a lot of String skips and chromatics, those excercises will make you pick a lot better.