Borrowed Time

(Based on the wizard spell, modified for warlock)

Reaching into your own future, you borrow energy and life force from your future self. Your present need is greater!

When you cast this spell, instead of consuming a spell slot, you may restore one.

For each spell slot restored this way, at your next short or long rest, those spell slots are NOT restored. In addition, when you finish your next short or long rest, for each spell slot restored this way, you take 1d8 Necrotic damage.

If the effects of this spell would bring you to 0 hit points, you can instead choose to be dropped to 1 hit point, and lose all spell slots for the next 2 short or long rests. If this occurs you also age 1 month for each point of damage past 0 you would have taken.