I've been diagnosed with depression, have been for around 9 years now, and just like what Dark Minx said, the whole 'depressed people are never happy' thing is a myth. I have days where I'm fully content, where it feels like I have no depression at all - but I still have it. I have many happy moments, but I still have depression.
People can have varying levels of depression. Some people are far worse off, and have way less positive moments, and more often than not have those hopeless, terrible moments. There are other people with more minor depression who have a lot of good days, but still have those bad days. It's very good to see you're dealing with it the best you can so far, try to keep that up!