Blood Barrier

You sap your own life force and project it into a shimmering red barrier that surrounds and protects you.  When you cast this spell you take 5 necrotic damage that cannot be reduced by resistances or immunities.  If this damage would cause your character to drop to 0 hit points then the spell fails.  After taking this damage you gain temporary hit points equal to twice the damage taken.  These last until you finish a long rest or until you receive temporary hit points from another source.

At Higher Levels. When you cast this spell using a spell slot of 2nd level or higher, the necrotic damage you take is increased by 5 for each spell level above 1st.