He did not lose three years. If you look at any timeline of SW, you'll see them say that ANH happens in some given year, ESB is equivalent to ANH+3 (years) and ROTJ is equal to ANH+4. This can be give or take a couple months, I'm sure. So, at most, Han was likely frozen 12 months. I don't know how it's possible to survive without food and water, but they do perform cryogenic freezings now in real life, so they must have something worked out.