One emotional outburst for which you feel sorry (and no you shouldn't strike your mom, but one slap is more like an outburst of emotion than an actual desire to cause physical harm) does not a horrible person make... and the fact that you are going to wait to have kids until you're ready to face managing your own mental health AND caring for children means you're definitely not a horrible person.

I am feeling the same way right now. I am almost right at the place I need to be to start having kids. I feel like I'm doing a good job managing my own mood troubles, but I'm aware they may arise again. So the next item on my agenda is to "out" myself, so to speak, to my parents, who don't know that I see a therapist or am on medication. I don't want my kid to feel like my occasional bad days are their fault, and I'm worried that's what will happen if it stays a secret. And I definitely don't want to be a mother that doesn't own her own problems, and instead allows them to burden her children.

It doesn't surprise me at all that you crave maternal affection. Your mom probably felt like she was far away even when she was right there.