My S.O. has depression, but I feel like an ass because I am really starting to resent him. What can I do?

I'm alone right now, for the first time in many months. (And by alone, I mean not in the presence of my fiancé).

I'm F23, he's M23. We have a two year old son, and we got engaged shortly after our son was born. We've been together for almost 5 years. We've never broken up or anything, but had some pretty bad fights over the course of our relationship, just the norm. So, here's where things get frustrating for me:

He's so unmotivated. Every. Little. Thing that needs to be done, I have to nag and nag and nag, and I stress about whether or not he's going to do them. That said, I absolutely hate what I have become to necessitate this lack of will to do the simplest tasks.

A few months ago, he was diagnosed with depression. I never really knew what it was that held him back so much, so I guess his recent diagnosis makes a lot of sense. I'm going to express my blatantly selfish feelings about it all because I really really want to get to some sort of solution with some unbiased opinions- his sickness feels like it's my fault, like I finally broke him (he says it's something he's dealt with long before he met me, and has only decided to acknowledge it now... may be true, he dropped out of high school because of intense social anxiety).

He's not very open, to the point where I wonder if he has thoughts or feelings about our relationship at all. I cannot express how much I want to hear his side of our disagreements, but it's like he doesn't disagree, he just "forgets" to be considerate towards me, or "forgets" to help me out with our kid/home/finances. Getting a genuine response from him is like squeezing water from a brick.

Honestly, I think I'm too high strung, and he is just waaaay too laid back about everything- whereas I worry about things to the point of paranoia, he puts them from his mind to the point of extreme neglect. He's a nice person... I think. He's not directly mean, I guess is what I want to say, i.e. he doesn't beat me or batter me verbally or cheat on me... in fact, he does nothing with me, unless I beg and beg. (Nag and nag and beg and beg).

I work 45+ hours a week at the moment, and I get to bring my son with me to work if need be. My S.O. is not working right now. He quit because of his depression. I feel like I have been supporting him as best I can; it's been about 6 months now since his diagnosis. I've been holding in A LOT (I guess that's why I am here) for fear of overloading him in his current state.

It's getting to be too much. I come home exhausted from work, child in tow, and nothing has been done! The house is a mess, no dinner, nothing. I'm not expecting him to become the "house wife" just because he's home all the time, but can I least expect him to clean up after himself? I don't know what sort of allowances he should get as far as being sick, so I didn't say anything for a while. Finally, I said it was disheartening to come home to him when he's sat around all day on the computer or watching T.V., especially when his doc said he should be making better habits, and getting in good routines. He agreed, said he'd try to do better, and that's as far as it went.

After some months of this (working all week, minding the son, working my ass off on weekends to get the house in order, etc), I am too exhausted to go on. I want to leave, look for rentals near my work, and move out. I laid in bed all day, and he knew I was pissed off. I asked him to take our boy, and go to a friend's house, so I could have some alone time.

At this point, I feel like we would both be better happier without each other, but taking our baby into consideration, I don't want to do anything incredibly stupid when it may just be that I am stressed out and not thinking clearly. Any advice to work through this, or is it a lost cause?

TL;DR Six months ago, my S.O. was diagnosed with depression. He quit his job, and since then, things have been really tough because I have had to do everything. I finally talked to him about it, and he said he'd try harder to be more motivated, but thus far has not followed through. I'm starting to resent him and feel like we would be better off without one another.