There is a difference between feeling depressed and having depression, which makes it hard to figure out what we need right now when - doesn't everybody feel like crap?
What you are feeling right now might be the entirely normal reaction to this currently abnormal world. Here is what's happening: everybody is experiencing trauma at the same time. Exhaustion, trouble concentrating, insomnia, hopelessness, these are common physical, emotional, and cognitive reactions to trauma. They are also symptoms of a depressive episode. And depression, the illness of depression can lead to serious complications, substance abuse, relationship problems, suicide. Not to mention that it simply sucks the joy out of living. Depression, the illness needs to be treated.
So do you need to see a doctor? It depends. A recent New York Times article can help you sort it out.