Whims of fortune

When you cast the spell and at the start of your turn during the spells duration, roll 3d6. On each of your turns you can use your bonus action to reroll any number of those dice. If you roll the same number on each of the dice, the spell ends and you get the following effects for the next minute:

• Whenever you cast a spell of 5th level or lower, you can do so without expending a spell slot. (Only once per turn)

• You regain 2d4 + your CON modifier (minimum of 1) hit points at the start of your turn.

This effect ends early if you become unconcious.