Elemental Barrier

You create a barrier of shimmering energy around yourself that absorbs the damage of attacks that hit you. When you cast this spell, gain temporary health equal to 2d6 + your spellcasting ability modifier, and choose one damage type of acid, cold, fire, force, lightning, poison or thunder. The shimmering energy changes in color to match the damage type chosen. 

While you have the temporary health you have resistance to bludgeoning, piercing, slashing, and the damage type chosen previously.

At higher levels. The amount of temporary health is increased by 1d6 per level above 3rd.