hi gp70,
welcome to the boards! just wondering before i write more, have you read any of the baby whisperer books? as you have probably deduced from reading other posts, this site is based on the advice that tracy hogg offered in the series of BW books. if you haven't already read them it might be useful to pick one up (perhaps the toddler book would be most helpful).
you gave lots of great information but it is not easy for me to pinpoint exactly what the problem is, though i have a few ideas. just wondering, have you ruled out teething? you mentioned him biting on the bars of his crib and waking in the night which he doesn't usually do, both made me think he could be cutting some teeth.
further the two things that stand out to me are how he is getting to sleep and his routine changing from you going back to work. regarding his routine, what time do you get home from work, and what happens then? i have read (i think in bw) about parents who come home shortly before bedtime and that gets the child all excited or upset and makes bedtimes difficult moments to settle. is the same thing happening at bedtimes on the weekends too?
regarding the way you get him to sleep, it also made me think that as he gets older, using a bottle to get him to sleep may begin to be much less effective as solids are a much more important part of his diet now and milk no longer has such a filling, relaxing effect. that was/is certainly the case for my ds anyway. so i am wondering if he is starting to need a new way to get to sleep, but so far this is the only method of falling asleep that he knows. therefore when bedtime comes around and he is not falling asleep from his bottle, he is getting very frustrated and upset because he is tired and expecting to sleep, but doesn't know how.
if this is the case then i would recommend doing some sleep training to teach him to sleep independently without a "prop" to get to sleep such as a bottle, you rocking him, etc. (i would actually recommend sleep training regardless of whether this is the problem or not, as eventually it will be a problem). ideally he should be drowsy and you leave his room while he's fully awake. the babywhisperer method suggests doing pick-up/put down (pu/pd) or, depending on where he is in his development, just put down. Here is a link to the faq's of that board where you can get more info:
http://babywhispererforums.com/index.php?board=89.0 sleep training will be best when you and your husband really have the time to dedicate to it and can committ to seeing it through until it's done. if you are in a particularly stressful time or will be, then perhaps it is best to rock him to sleep now and begin the training as soon as it is a good moment for you.
hope this helps, keep us posted in any case on how you get on. x
