Thanks a lot for you reply.
I'm currently trying this out. It's quite similar to what I had in mind anyway. I think that it's possible that I also have a few other things not wired in the conventional way but I don't think it's a good idea if I try to do a self diagnosis at all, let alone over a public forum.
Somebody, homeomorphic I believe, mentioned that Henri Poincare worked on mathematics for only 4 hours each day. I looked it up on wikipedia and apparently he would do many things in a systematic manner and would study from 10 00 to 12 00 and then again from 17 00 to 19 00. Is this not a little similar to the "methods" we're talking about?
Another thing that's been helping is having some music play simultaneously. I won't pay full attention to it at all times but I will occasionally (especially when I start getting bored or when there's a section that catches my attention, I suppose) stop to listen for a minute or two.
There's also the "not being afraid to change subjects" bit, which resembles the "do 1 hour, then gym, another hour, then something else" strategy you mentioned. The "fear" here is really "if I switch between tasks so much, will ever be able to finish anything?" but the trick is that I will be doing instead of thinking, meaning that I will still be progressing.