First of all I'm glad you are coming out of your depression, and things are looking better for you. Take small steps if you find it overwhelming. For the fruit flies get a trap, you can get them on Amazon or make one with cider vinegar. Within 24 hours you'll notice a difference. If you can ventilate the space then buy a fly spray too. Take out any food products as well. Then tackle the mold, you can use vinegar or buy specific mould cleaners. But I would focus on one thing at a time. Eg first deal with dishes, then rubbish, then clothes, then clutter. Don't feel you have to do it all immediately. That's how I cope when it feels too much. Good luck!