absent or abusive.. which is worse?

.

.

.

.

.

.

.

Okay, I've struggled with severe depression since the age of eight. Currently I'm on the verge of turning twenty six and I have a three year old child. My depression inhibits my ability to judge situations, and it makes me quick to anger and short on patience. This results in me screaming at my kid sometimes and grabbing/spanking harder than necessary. I feel like a horrible mother and I've been considering turning full custody over to his father but I keep hearing that an absent mother is worse than an abusive mother. I want the thoughts of other eve moms on this. It's a sensitive subject for me and a constant struggle that just feeds back into my illness. I just don't know what to do.