Some more thoughts --(a) you said something about getting back to full strength. does that mean that you're waiting/resting/camping? if so, the monsters *will* just respawn, probably as fast or faster than you can get rid of them. having one or more regenerative items really helps in that regard (both hp and sp regen).
(b) if you have the option, turn the difficulty level down. that won't help so much with the monsters already spawned, but it may reduce the number and type of monsters spawning in the future.
(c) as llevram said, it's key to get into a more defensible position -- some of the critters are fast and will surround you, making battles harder than they need to be.
(d) most of the monsters in bayjin are most vulnerable to fire. stock up on fire magics.
(e) if you're having a lot of trouble with rynjin spellcasting, you need to boost your mental/divine resistances. cast soul shield fast and at a high level, and/or pick up some appropriate reistance items.