6 Months - slowed weight gain, trouble pumping, + sleep issues - related?

Obviously cause for concern and we are set up for a weight check in a month (we are about 2 weeks in)

At the same time I've been struggling to pump enough milk for her at work.  I've added a pump session (every day even if I don't work) after morning feed and before bed.  Between those pump sessions and what I get at work I'm able to keep up with her through the week.  Sometimes I'm skimming through - but I make it.

we have started solids (per ped) and upped them (per ped)

On the weekends we exclusively nurse and she is just as happy, content and sleeps just as much.  Due to this I don't feel I have a supply issue.. HOWEVER.. I'm concerned.

Her sleep sucks.  There is just no other way to put it.  And its not the normal - won't sleep, or gets up all the time.. She self soothes for naps going down awake - for bedtime she GENERALLY nurses to sleep (thinking this may be part of my issue).  She goes down around 7/8pm and then wakes up somtime between 12 - 4 and nurses - its about 70% of the time she won't go back to sleep.  She's happy for up to 1-2 hours playing in her crib and if I go to her even if she starts to fuss she smiles big and gets excited until she realizes I'm not getting her up.  Some nights she struggles to go to sleep - those nights I worry.  Those nights I fret about my supply.

These odd wakings + the slowed gain have me all freaked out that she's not eating enough (along with my pumping issues) - Anyone have anything similiar?  Any advice?  I'm working on getting a scale to ease my mind a little...