Just last night I looked at my hubby and told him that I was bummed he was going to work today because I just wasn't up to playing 'mom' today to the (step) kids. He is great about being understanding about those things, but doesn't completely get it.
Actually, my hubby gets it better than most, and I'm very lucky about that, but the whole world isn't like him.
There's always going to be people who just don't get it, sad but true. When things get bad I do find it's better to talk to those who understand what it's like to feel like crap so much of the time. Being online here helps, and I have a good friend who is chronically ill and completely understands how it is to deal day in and day out.
Each and every day is different, so something that helped one day might not help the next. Remembering that you are NOT alone in all this crap, and there's always someone there to talk to is a big weight off my shoulders.
Also, getting it off your chest - whether anyone reads it or not - can really help. In fact, when I was in the potty a few minutes ago I had a very low moment, so I pulled out my phone, got into Google Docs and vented. I have a document set up just for those moments. Do I feel better physically? Nope, but I was able to come out of the potty and face the kids without having a crying jag.
One last thing, I agree with the person who said to have your levels checked. I'm almost guaranteed to be down in the dumps further and faster if by B12 is low (as it is right now). It's very important to stay on top of these numbers so you can take care of them before they bring your health and peace of mind down with them.