Amina, sometimes the things around you can make you depressed without you even knowing it. For me, just being in a white room can make me miserable. I know you're renting your home, but you could ask the landlord for permission to paint (because most rentals are beige, lol) and promise to repaint before you move out. Even if it's just one wall in your favorite color, that will make a big difference. Really!
Another thing that I noticed last year was lighting. I know others have mentioned it, and this is so true too. I broke my turtle's sun lamp and when I replaced it, I bought one that lets the light stream everywhere instead of just a spotlight, and this is so much nicer! It's emitting ultraviolet to mimic the sun (for his health) and it's made my mood brighter too. Funny but it works.
Plants bring nature into the home, and that cheers me up. I have tons everywhere, too many in fact, lol. But changing your home environment could be just the thing you need.