I was in your shoes last year! My dd was always between "below, or off the chart" and up to 10% for weight, always gaining slowly. I bf her for 18 months and held off solids until 6 months. The entire time I bf'd I never felt "full", only slightly in the mornings. At 21 months she now eats EVERYTHING (healthy) and actually has some chub and rolls on her frame but will always probably be light weight as dh and I are. Has your lo always been on the light side? If so, I wouldn't worry about the weight.
I tried the Fenugreek and Blessed Thistle combo and it didn't seem to make any difference for me but it did a lot for my mind as I convinced myself it worked so I was more relaxed and not as worried about bfing and supply. I had no side effects.
At what times are you giving the cereal? Just make sure you're bfing prior to giving the cereal as your supply will decrease with adding solids but decrease to what is needed (remember, supply = demand).
Every now and then I shortened feed times to go back to 3ish hours, just to boost my supply but again, it was only temporary, as it would adjust back when we returned to the 4 hour feeds.
Hopefully your stress level from the move should level off now, this will help, and try to get some rest in the afternoon if possible. I find that as moms we do so much in the day, especially before and around dinner time, we are running around always.
Hugs and good luck to you! Hang in there, you're doing a great job with bfing to have come this far along.