My daughter goes through these stages and we try to blame it on gas or teething or a growth spurt but we never know. My daughter is a year now and she still wakes up once a night for a bottle, but it is progressively happening later, she can now sleep for almost 9 hours without a bottle which is a big improvement since at 8 months she was still waking up every 3 hours.
Personally I think every child is different with their sleep habits and you just have to find what works for you. With my daughter if she gets sick and her sleep is affected she needs to catch up before she can sleep well again. For example, last week she had a cold and was waking up more and not sleeping as soundly (we could hear her on the monitor moving around and coughing). After she was better she starting waking up more and crying for us. I brought her in bed with us when she woke up one night and she slept really well and the next night she slept the whole night in her crib back on her normal schedule of waking for a bottle and going back to sleep. I know a lot of people would say not to let her sleep with us, but it works for us and got her back on schedule without us losing a lot of sleep.
I read HSHHC by the way and it did not work for us. My daughter would scream for a very long time and would get herself more worked up as she went along. We have tried a few times. The last time we tried before her first birthday. We modified it slightly and stayed in the room with her. She didn't cry as hard as the previous times, and she mainly fussed with just a little crying or she would sit up and stand up in her crib and it took over an hour to get her to sleep for an week straight. She was definitely tired but just couldn't fall asleep. Then she would sleep poorly and wake up a lot at night. We went back to letting her fall asleep with us holding her and it went back to taking about 15 minutes to get her to sleep and she slept better. Again, a long post to say here is what works for us, hopefully you find something that works for you soon.
Good Luck.
D.