I think the best thing I did to make it through each day was to give up trying to control everything. It's hard, but in the end if you realise that this little person is now deciding what gets done when, it makes it a bit easier. I stopped getting stressed about not showering for 3 days
Getting a break is also very important, I found. We scrounged some money and paid for an au pair to come in 3 mornings a week for about 4 hours. I would either get out of the house and go for some coffee, or something fun and relaxing, or if I'd had a bad night I'd lock myself in my room and just sleep. I was really lucky to find the girl I did - I was completely open with her about my PND and she'd do lots of little things, like make me coffee! Or pick up things from the shop for me! Absolute heaven in those first few months!
If I have another child I plan to have an ARMY of helpers waiting in the wings! It makes such a difference to have little things like a clean house and someone to give you an hour or two to get some sleep or go for a soak in a bubble bath!
I know you won't believe me, but it DOES get easier as they get older. I found that 1 year I finally felt like my life might actually
be normal again one day! So just hang in there...