You can get an LC to come out to do a home visit today. I can recommend a couple in your area if you PM me. I got one at 2 weeks to come on a long weekend and she helped build my confidence, and I've just dropped in at the maternal child health clinic this morning and had an LC there watch me feed and did a refresher. See if you can get in this afternoon because it can do the trick for your 5 days away?
If baby is not latching on properly then he is not effectively sucking hence not putting on weight, and takes forever to feed, If he is latching on properly and sucking effectively it shouldn't take forever. Also I think you're pumping too long, 10mins on each side has been the advice given to me consistently by the hospital as well as the LC's. I hired a Medela pump and it does the nipple stim thingy for 2 mins. You need to look at the flange size ?too small or if your pump pressure has been dialled too high for your comfort. The other thing is if your nipples are damaged it can hurt if that part touches the flange. It might be worth using a nipple shield while you let your nipple heal.
The baby is more effective at stimulating the breast to increase supply than the pump. I had low supply problems in the first 2.5 weeks, on the advice of the LC, I started Motilium, then Fenugreek and Milk Thistle. Also pumping in between feeds, aim a total of 8-9 times of either BF or pumping per day. If your baby is not gaining weight it'll be almost 2 hourly. I was told to aim for 150ml per kg weight in 24 hours.