Baby refusing all milk

Er

So my son just turned 11 months old. I was still nursing 4 times a day while we were on lockdown but I wasn’t bothering to pump. When I was notified that I would be returning to work I tried to pump and got zero. So I know my supply has tanked. My son loves water and eats plenty of yogurt and cheese. In fact, he eats anything we give him. The only thing he has started refusing is milk of kind. Our pediatrician said we could start transitioning him to whole milk but he flat out refuses it. I don’t have enough milk to pump and mix with the cows milk and he will no longer drink the frozen breast milk that we have. Our pediatrician also said we could try milk alternatives like oat milk and almond but he does not like those either. The only type he will even drink a little bit of is coconut milk but it’s only maybe 4 oz in an entire day.

I know the goal is for him to get enough calcium and vitamin d so my question is, do any of you ladies use calcium supplements or another source of calcium for your babes? He takes a vitamin d + probiotic so he gets plenty vitamin d. I’ve just been trying to get 4 or more servings of dairy in him a day but I also would like some other options for him. He may eventually be fine with cows milk but I want to make sure he’s getting the nutrition he needs now however I can.