Try some Aqua Vitalis and Bucks Blood potions before a fight.
I believe both give you 10 minutes of protection.
That should give you some time.
But of course, a lot will depend on your armour/ weapon protection and condition.
You should also consider strategic moves.
If you back up to a wall, no one can attack you from that direction.
Same goes for trees and other diverse objects.
I found many YouTube videos helpful on strategic fighting and fighting mechanics.
Also apply poison to your weapons.
I apply Bane Poison, which I believe is the deadliest in the game, but you will have to bloody your enemy.