Hi,
After visiting Portsmith I found out that my Health is no longer regenerating after rest.
Members of my party still can be healed by spells and in the temple.
Could I be under infuence of some evil spell, or I simply broke the game?

Are your characters sick or something?

I've read that, at least in MM2 (which is similar in many ways to MM1), a character who is diseased can't be healed by rest. So, maybe try curing the disease and then resting?

Also, at least in MM2 a character who is poisoned will have their max HP reduced to half its normal value when resting. This can be fixed by curing the poison and then resting again.

Oops!

I now know what lack of food does in this game.
(Watch out for deserts! I hear they may not be good for your food supply in some of the games.)

Also, don't forget the Create Food spell; it might help if you get into a bind (provided you have enough SP to cast it, of course).