The only thing I can really say about the size of bottles is that they do make 9oz bottles and I have definitely heard of friends' babies that drank that much. I almost exclusively nursed and the few bottles I pumped were usually more like 5 oz. But mine tended not to drink so much when I wasn't there.
They can start doing a lot more around 4 months. I'm pretty sure there is a growth spurt around that time. That might explain her larger need for milk. Also, teeth can start moving and make their little mouths sore. You may or may not see any teeth for several months, but there is action under the gums before you see those new shiny teeth pop through. My first actually had a tooth pop out at 4 months 1 day! The other thing that can be going on is they can begin gaining mobility. Rolling over happens around that time if it hasn't yet. Mine always had disrupted sleep when they were learning a new skill. It was like they didn't have time to sleep.
I guess if she's drinking more, it makes sense that she's wetting more. Usually the diapers come in ranges of sizes that overlap. While she might really fit well in a size 2, if you check the packaging, she might also be in the size range for a 3. You don't want a diaper that is too huge, but if you can make it not have gaps, using the next size up just for bedtime can help with leaks. That's where we are with my 12 month old. Huggies makes an overnight diaper too which work great. They are hard to find in a size 3 (they don't make under that). I can usually get 4's or 5's at Target for my older one though. Giant Eagle used to carry them, but not lately.
As for the fussiness - her sleep is being disrupted and she could be uncomfortable if it's her teeth.
If you just don't feel right and none of those things seem to fit, it never hurts to call the ped and ask. They will either tell you over the phone (ask to talk with a nurse) that everything is ok and let you know at what point they would be concerned and want to see your daughter or they will just tell you to bring her in.