I also had similar situations with both of my children, specifically around this age. For one of them I had to always take him into a quite room, or even lie down with him in bed and nurse him. The other one had a period where he would only nurse at night, I suspect because it was quiet and dark, and he was not as alert. Here are a couple of my thoughts:
- a visit to the pediatrician wouldn't hurt just to rule out an ear infection
- try switching the nipple on his bottles to a slower drip nipple. He may not have patience for the rate at which the breastmilk comes out when he nurses because he has developed a preference for the fast flow of the bottle.
- pump at least as often as he would nurse if he would nurse exclusively, i.e., every 3-4 hours. Don't pay so much attention to how much milk you produce, as long as you pump and provide stimulation this will keep your milk supply.
- also, you can buy fenugreek at a vitamin or health food store in a capsule form. You can take two capsules three times a day for 4-7 days and you should see an increase in your milk supply.
- if you don't already, try co-sleeping with him at night. This will encourage him to nurse when you are with him because you are sleeping together. Not only will both of you find comfort and closeness, but he will be very likely to nurse in this quiet, calm sleepy state.
Lastly, I think it helps to understand what is going on developmentally at this time. He is very aware of things around him - everything is stimulating. He can interact with his world more - he can touch, grap and play with objects, he knows how to make expressions to elicit certain reactions with people, he knows how to vocalize to get what he wants. He is or will be interested in food. Ultimately, you are the most important thing in his life right now and the closeness and relationship that you have with your baby is what helps him thrive. At his age now, nursing is becoming not just nutrional, but also a way to connect with you and find comfort.
A last thought, you could also try taking a bath with him. My kids definitely enjoyed this when they were babies, and sometimes would spontaneously want to nurse.
Good luck! It sounds like you are doing everything that you can!