Re: first oversupply, now not producing enough!?!?
pooping less is also normal after 6 weeks - some exclusively breastfed babies go longer than a week between poops, and as long as they're not in pain, that's perfectly fine. fussy is also par for the course now, particularly afternoons/evenings.
how are you pumping? pump output is generally unrelated to nursing output. this is in addition to full nursing, right? so it is normal to not get very much, if your supply and demand is well-matched: your body is making what baby needs, not extra! but in any case, you only need enough for the first day, because during that day you'll pump for the 2nd day. it's nice to have an extra bottle or two, but still, we're not talking huge amounts. don't even worry about it till 2 weeks before you return, then just add in 1 pump a day, combine to 3 oz bottles, and you'll be fine. there's lots of info on this site about how to do that - check out the pumping/working forum.
Nursing, pumping, cloth-diapering, babywearing, working professor mama with the awesomest SAHD ever.