Depression?

So, I have been crying non-stop the past 3 days for what I feel is like no reason at all. I don't know if this has to do with some type of hormonal imbalance or just plain depression. Today I had to leave the house so I could cry alone. I feel lonely even though I'm surrounded by people who love me. When I'm asked "what's wrong?" I can't explain and just cry some more. This is driving me crazy and I don't feel normal. Has anyone ever gone through this? Should I seek professional help?