Sleep(How much is too much?)

I think I have a problem with sleep. No matter when I sleep how long or how many times I sleep(during the day) I always wake up feeling tired. I probably would be asleep and unavailable most days if it wasn’t for my job(even then I can catch myself daydreaming and and zoning out).

I only just woke up 20 minutes ago from a 5hr nap and I still feel tired and I have work in about an hour. I only have one job so I don’t think it’s a physical issue and I was like this before I was hired. Any advice on my situation would be greatly appreciated.