Sorry to interject here, but I think this is an excellent question. And I thought it might be helpful to get input from more than one person. Luckily (ha,ha), I'm feeling anxiety right now, so I can definitely describe it to you. For me, it feels like this extreme nervousness and feeling of dread in the pit of my stomach. My mind starts racing and I have a hard time concentrating on anything. And I feel fidgety, like I can't sit still. Back when it was really bad, I was irritable, well it was more like rage. I felt like what a drug addict must feel like when they need a fix. Because I felt crazed and out of control.
Now, how do you know if you have Depression or if you're just feeling down?