sleeping regression

XiaoXiong is going through a sleeping regression. it has been terrible last couple of nights. it started last week, he would up between 1-3am and screaming unless I picked him up, sometime I could pat him back to sleep, but mostly we would end up co-sleep on my bed till the morning. I thought maybe he is over tired and according to askMoxie.com "between 7-8pm is the sweet spot for baby to go to bed" and "the early they go the later they wake up" so we tried to put him down at 7:30 on Sat. he woke up every hour but we were albe to put him back but then it came to the midnight strike, he was up and wet and mad, we changed him but he wouldn't stop crying, we hold him, cuddling, walking, singing, rocking .... nothing worked, he just screamed his lung out. after 30 min, we were both frustrated, so we put him in his crib and we sat in the dark and waited, he stood there screaming for 10 min then he sat down screaming, then lying there screaming .. he'd stop for a few min then started again (even harder and louder). it was unbelievable. you won't ever think a little person could have that much energy and endurance. I gave up and picked him up again and Alex made a 4oz bottle for him. we were not sure why he was upset at the first place, but he gotta be hungry now. he drunk the whole bottle with one breath and cried in my arm for 5-10 mins before felt asleep. he was tired the next day. took two 1-2 hours naps on Sunday. we put him down at 8pm then he woke up 1:30 and cried for 10 min b4 I picked him up and he continued for about 20 min until alex came upstairs and took over, he cried on and off for another 20 mins. Alex managed to put him down and patted him to sleep. then he screamed every 20-30 min (but I only had to got up and pat him twice) that last for about 45-60 min before he finally settled down. he got up 6:30 this morning, I nursed him and he gone back to sleep in my arm till 7:45. he moans every 20 mins though ... I don't know what is his problem but the last a couple of nights had been terrible. he was tired this morning and ZhangJing told me that he was grumpy and weepy all day. ;-( btw, we gave him 9 oz. last night and I changed his diaper before I went to bed at 11:00. and I rubbed his gum while he was crying at night, didn't help ...