FBG, am I right that you're dieting? I wanted to post this the other day when you listed the measly amount you'd eaten - my first thought was, there's a meltdown waiting to happen (in a caring, not judgy way, obviously.)
I didn't post then because I mainly lurk and you don't know me from Adam - me jumping in and telling you you'll be struggling soon would probably not be the right thing to do.
However, now you're asking for advice, and I can tell you what I've learned and what a lot of others know in more detail and with more qualifications than me.
You need to nourish your body with the right foods. Mood swings and depression are often caused by chemical imbalances in the brain, as a result of poor nourishment.
If you're overweight you probably think you can't possibly be under-nourished, but I'm guessing you have a taste for sweet stuff and whiite carbs.
In fact, when you eat this stuff you're self-medicati g for your depression as the sugar (and this is what all white carbs are just as much as actual sweet stuff) gives you a quick 'hit' by spiking you blood sugar levels; it feels great, until your Bs drops tenfold later, draining your energy and making you snappy and short-tempered, or depressed, and longi g for your next 'hit.' that's when people go to the biscuit tin, the wine bottle, or the chocalate to make themselves feel good again.
There is a website called www.radiantrecovery.com which gives more info, or you can buy various books on Anazon (the first one was Potatoes Not Prozac).
Basically you need to eat protein every meal, brown carbs, and as much green veg as possible. You learn to use food to stabilize your mood rather than send you up and down. And you can lose weight.
Sorry this is long and preachy - I know it works, and you could start to feel better in no time.