CMA AWARDS and pumping!

So I’m going to the CMA Awards in Nashville next month and I will be away from my 15 month old for the very first time. I’ll be gone 2 days. I pumped kinda frequently in the beginning to build a stash. Unfortunately we didn’t use the stash and now it’s gone bad. I stay home with her so I haven’t needed to pump in probably 8 months or so. But we still nurse 2-4 times a day. I’m trying to get enough milk for while I’m gone, my body just isn’t reacting to the pump like it used to! It took 20 min to get 1 oz!! Any tips to try? I tried pumping while she nursed on the other side and was still only able to get an ounce. :/