You need to check your equipment and personas then. With the right persona, almost nothing should be able to kill your MC, especially not bosses.
What spells is he killing you with? Or is it phys attacks? Creating personas that are strong to these things help. Some really good personas are strong against multiple elements and weak to nothing.
It's been a couple weeks since I played the game. You may want to post this issue on the gamefaqs.com boards as you'll surely get a lot of help from people playing the game now like you. The faqs there may help as well.
"Dr. Tenma, according to you, lives are equal. That's why I live today. But you must have realised it by now...the only thing people are equal in is death"---Johann Liebert (MONSTER)
"WAR is a racket. It always has been.
It is possibly the oldest, easily the most profitable, surely the most vicious. It is the only one international in scope. It is the only one in which the profits are reckoned in dollars and the losses in lives"---Maj. Gen. Smedley Butler
