Hoya. i'm not a BFing expert but i think you need to encourage daytime feedling to avoid future problems and to try and get lo sleeping a bit better at night. The best way to do this is offer feed frequently throughout the day even if you are out.
Maybe for the next week or so dont let her go more than 3 hours from 7-7pm without feeding. So try her at 7, 10, 1pm 4pm and 7pm for bedtime. If she doesnt want any, thats fine, but at least she has the option. She may surprise you. I always found that when we were out and about, my DS got very disctracted when i tried to feed him and ended up taking very little, and just as you are describing i ended up paying the price in the night.
So try the 3 hour feeding for 1 week and see if that improves things.
She is getting to an age where 1-2 feeds during the night (hopefully 1 before you go to bed and maybe 1 more) should be do-able and hopefully things will get better very soon
HTH
Lili xx