You are being too hard on yourself! Have you tried self-analyzing of what cause you to feel this way. MDD is a bio disease that feels physiological but... there are stressors that trigger you into that state. Think back...

I suffered from dysthymia and later went to MDD so I can relate to what you are saying. My chest felt so constricted and I cannot cry even though I was desperate to do it. I couldn't concentrate and I started to feel very inadequate. No matter what I do... nothing worked! I started self isolation and had the worst self-image ever! Not even talk therapy helped.

But I also started an exercise program. I ran every other day. It didn't help me from coming out of MDD but it kept me afloat and I had a goal every other day... to run and run an extra half a lap until I was able to do 10 laps (and imagine... I used to hate running). I discipline myself to do it even if I was feeling dejected or lethargic. After awhile... I was able to add on more programs like waking up @ 5:30 to Denise Austin and walk during breaks, etc.. etc...

I still felt empty but at least I wasn't moping around the house anymore. Slowly but surely... I started to be open to friends about my condition and surprisingly... they're very sympathetic and asked me out to lunch or dinner. I went, though I couldn't keep up w. the convo but listening to their life dramas... made me feel slightly better.

Start slowly... and even though you don't feel like it... do it anyway. You'd feel worse if you realize that not only you're in a state of dejection, chest constriction but also you haven't done a thing. If you do something... at least you can say to yourself... hey... I managed to complete this, though it was hard - that means that I'm still good enough to do other tasks (and you always are... don't ever give in believing that you're not). They maybe 3x more difficult than it used to but it is better than doing nothing!

No one can help your get out of depression and you will never "come out". Sometimes it helps me to read stories about depression because it makes me feel that someone understands me and that I'm not alone. You know that it is hard and frustrating to explain how you feel to a person who never experienced it of had regular exposure to depression so... find something where you can feel understood.

I particularly love reading the Epilogue passage from An Unquiet Mind by Kay Jamison.