Hope this isn't the end

So the last week my milk supply has drastically dropped. I was told since I took allegra for 3 days straight it was drying me up. I immediately stopped taking the allegra however I'm still pumping about an ounce from each breast after 15 minutes on each side. I have increased my water as well as I already have been drinking mothers milk tea and taking fenugreek capsules since giving birth. Before I took the allegra I was pumping 4 oz from each breast in one sitting. I'm super frustrated and I'm wondering does anyone know if my milk will go back to normal or is there something i should do? I am supplementing so my babies are getting full formula for now.