I think he sounds like he is doing fine, nutritionally, and don't think this will result in a supply drop so marked that it ends breastfeeding. I have noticed all of my babies and many of my friends babies get very fussy nursing right around that time- the top teeth really effect nursing, and they have to relearn a good latch- and then there is so much MORE the are noticing about the world, that they want to be down and doing and seeing (this happens around 4 months, too, and both times will often cause sleep hiccups)- and they are often becoming more mobile at that time- progressive rolling, scootching, or crawling. They are also pretty efficient nursers usually at that age. They usually will pick up a couple nursing sessions when separation anxiety kicks in/back in.
For pumping, depending on how much time/money/effort you want to put into it, there are things you can do. Pumping at a consistent time is huge. As a SAHM, I never had the need nor structure, and thus never really got good at producing for the pump. Bah. I did find I could get a LOT off the side the kid did not nurse on, first thing in the morning.
For supply, I like Goat's Rue. I have not heard of any contraindications for it, but you would still want to check with your doctor or an IBCLC first, of course. Way better booster than fenugreek. Oh, and a diet with enough fiber and complex carbohydrates. For milk ejection, like for the pump, adding red raspberry leaf helps.
For more on pumping technique: http://lactationmatters.wordpress.co...-is-important/