Sometimes when people around us know and see how we are "really" feeling it brings it to face to us. I dont know about you but alot of times, I feel bad and guilty for being depressed, that I bring it on for others.
If your friend said something than they care enough for you to talk about it, can you open up there and tell them whats been going on? Even being able to talk face to face to someone you know about the secrets (depression) youve been keeping helps. It wont be a secret anymore.
I hope tomorrow treats you better than today, Hugs.