No two kids are alike

I know that no two kids are alike. However, after you have one, you feel like you have seen a lot, have experienced a lot and are (or should be) more comfortable handling the curve balls that a new little one sends your way. WRONG!!
Mason did not prepare me in any way for Miles. Mason had his issues, don't get me wrong. But, they were very different than the issues that Miles has had so far. Miles is still not sleeping. According to the ENT, Miles has 6 teeth that are close to cutting through. He was up every 3 hours last night (10:30, 1:30, 4:30 and 7:30) like clockwork. I feel like I am the sleep-deprived mom of a newborn again. Except my "newborn" is almost 11 months old, 21 lbs and very strong. He is harder to comfort because he is able to throw his weight around. He has also drastically reduced the formula he is taking. On Friday, I noticed a drop in the amount he was taking at each feeding, and by Sunday, I was having to force formula on him. He is supposed to take in 17 oz each day (based on his weight). Yesterday he took in 16 oz. A week ago, he was taking 30-32 oz a day with no problem. Last night, he also threw up the 4 oz he took at bedtime and his entire dinner. All over him and me. Yuck. Eric wasn't home yet. Mason wanted to see (boys have weird interests!!) and started gagging. Thankfully, he left the room when I told him to without adding to the mess! I thought we were done with the throwing up and the majority of the spitting up. I guess not.
So, the slow-down of eating could be one of several things: 1)his teeth hurt and he doesn't want to suck on the bottle, 2)I stopped his prevacid last week (per the GIs instructions) and he could be refluxing and hurting, thus he doesn't want to eat, 3) he is more interested in eating solids than bottles, 4) he went several days without pooping and tummy could have been upset/full and didn't want to eat, 5) just trying something new - "let's not really take any bottles and see what mommy does" 6) I have no idea.....
I think it is some combination of the above - maybe 1, 2 and 4 are my most likely thoughts. Any other suggestions? I am totally open to any advice! At least I know it isn't (or better not be) his ears this time. Ahhhhhhh, my silver lining! :)