I hate this feeling, because it tends to get worse and worse until it can't get any worse and then I know my mood will lift again
I think the key thing from this sentence is the end bit.
You KNOW your mood will lift again so waiting it out will see you right.
Can you remember back, it wasn't that long ago you never thought you'd feel happy again, now you know you will and this is just a cycle.
What could be interesting is tracking this cycle. You have your highs and your lows but as time goes on you'll be able to see that those lows don't last as long and aren't so deep because you know there'll be an end to them to look forward to.
I reckon that's pretty positive actually. 
I don't post so much anymore because you've got a good support network of people who know how you feel. I'm watching your thread though just in case I can contribute anything sensible.
Keep going Mo, your reward is your next high 