weaning :(

my son has been excusivly breastfed for 6 months then we put him on solids and breast milk he hasn't he formula. he is turning 1 in 2 weeks and he's weaning off the breast slowly himself, I'm pregnant so my supply isn't great, and I read the taste changes while pregnant too so I'd assume that's why he's weaning. anyway I was wondering if I should be putting him on formula this late in the game since I don't think he gets enough breast milk or should I just give him cow or goat milk. he's plenty hydrated he drinks water and almond milk a lot though out the day I doubt he nurses to hydrate or eat anymore I think he just does it for comfort and routine.