When my second was a year old he slept (or didn't sleep
: ) like your child. Looking back, I can see that the PPD started then, but I didn't see it at the time. At 15 months I finally nightweaned him and was able to get about five hours of sleep a night on good nights. Unfortunately, the illness had begun. Mine manifested itself in anxiety about my health. I found a lump in my breast and was sure that I had cancer (my mom had breast cancer at age 30 so it was a reasonable fear) but that the doctors weren't taking me seriously. Turns out that I had caused the lump trying to get rid of a plugged duct and it went away on it's own in a couple months. Then I began to have heart symptoms and spent a summer being dismissed by my doctor and told I was a hypochondriac. However the symptoms were real, they just weren't caused by my heart, but rather they were a reaction coming from my brain and the anxiety.
Then my body started to give out and I couldn't eat, I had all sorts of strange symptoms that I couldn't figure out, I got so bad that I couldn't get out of bed or care for my kids anymore. At this time it was roughly a year from the time I think it all began. Finally my dh wisely took me to the ER thinking there was medically something really wrong with me, and they admitted me to the hospital for six days, diagnosing me with clinical depression. I am so thankful for the ER doctors who knew what was wrong with me as soon as I walked in the door. I don't know why that diagnosis came as such a surprise to me since my mother has had depression for as long as I can remember. It was hard since I wasn't really "depressed." I was happy with my life and had no real "issues" to deal with. Why my doctor blew me off, I'll never know. I was put on meds and given the chance to get my strength and appetite back in the hospital, and I am very thankful for those six days. I don't think I would have recovered nearly as fast if I had been put on meds and sent home. I was too sick at that point.
I highly recommend making that appointment with the doctor and getting help now. Don't do what I did and let it get that far. I shouldn't beat myself up too much, after all, I was trying to get help, I just had a loser doctor.
Let us know how your appointment goes. Don't feel bad about needing meds. Depression is a brain chemistry issue. The meds taken for the appropriate time frame (typically a minimum of 6 months) help the seretonin get back on track. For me I see it as a chemical issue not a charactor flaw.
Also, as far as the night weaning goes, I simply cut out all the feedings between 11:00 and the time the sun came up. It took 3 or 4 weeks but we got there. I would still go into his room and sit with him (we didn't co-sleep at that point) and offer him a sippy cup with water, but I didn't feed him. It was hard to hear him cry, but I was with him rather than letting him cio. I sang to him, talked to him and rocked him back to sleep. Also, if he would wake up at 4:00 am for example and cried until 5:00 when the sun came up, I still made him go back to sleep again before I would nurse him. I didn't want him to think if he just cried and cried that I would give in and feed him. He didn't understand the sun coming up thing at first and I though that feeding him after crying because the sun had come up would confuse him when he would wake at 1:00 and want to be fed.
Good luck, and I hope you get the sleep you need soon.