Dr. Mario isn't as difficult as you think, maybe you just need more time with it or something. I'm a pretty mediocre gamer when it comes to "da skillz" and Dr. Mario is no problem.
The key is.....if you put a pill somewhere that doesn't match....DON'T PANIC. Just go with it. Do what you need to do and don't stress about it. I've dug myself into what seemed like insurmountable holes before, but never forget that you can get the viruses from a horizontal angle as well!
Sometimes I've had multiple colors on top of a virus but I'll just attack it from the side. If you think about it, there are only 3 possible colors you're dealing with: blue, yellow, and red. You can't go all THAT wrong with such limited possibilities.