Struggling with Depression and Socializing

Honestly, I'd say that reaction is probably due more to anxiety. I've had to explain that to friends too. What I've done in the past to smoothe things over is just apologize sincerely, but explain that when you're anxious and depressed, you just get overwhelmed emotionally and accidentally respond that way. Talk to your friend about what you're experiencing, what's causing your stress and maybe set some boundaries. Try to be aware of when you're feeling this way and give your friend the heads up so they know not to disturb you. My best friend of 15 years also struggles with depression and anxiety, so when I explained this to her, she was very understanding. Maybe your friend will be too.