Maybe try some voluntary work in an area/place you feel comfortable to begin to break the habit of thinking you need to sleep. It's a bit like giving up alcohol or smoking ..it CAN be done..
I used to have the same sleeping schedule. When you sleep too much it makes you more tired. This is causing a viscous cycle. If your not already depressed it can make you depressed if you aren't careful. It can be fixed by forcing yourself to get up at an early hour. You can do it gradually. An hour or two earlier everyday untill you are satisfied with the time. Then the hour you go to bed will naturally adjust. You may be tired the first few days, but you will feel much better and more productive as you adjust. Sleeping too much and feeling tired all the time is a symptom if depression so you may want to talk to your doctor about it. I've talked to a lot of people with bipolar and we can all agree that your sleeping schedule is a great indicator of mood, and I think changing your mood can start with changing your sleep pattern. I go to bed between 8-10 pm and wake up between 7-9 am every morning. I feel very refreshed and full of energy every morning and never get tired during the day. But I'll tell you, I used to think I could sleep all the time and that was just my normal sleep pattern. This new schedule feels more normal and i feel more alive. Hope this helps, and good luck!
You could be depressed or have any number of medical conditions such as hypothyroidism or anemia. Get yourself to a doctor!