Dynamic difficulty?

[slashCo]

Hi everyone, I'm a fairly new player to this game and so far I'm doing pretty well (I've played a lot of HOMM3 so some things were familiar) but I noticed that it's getting a lot harder now. Basically, I finished up the starting continent, just gathering everything, getting experience, treasure etc. Now I'm at the Freedom Islands, and every enemy group I meet is rated "strong", "very strong" or "overpowering". It seems I can't defeat them without losing at least a part of my army each time, and replenishing them can be a pain.

Is this normal, or is it because I took my time to grow before getting here? Or will it get harder from here? Thanks.