Pumping issues

Ti
All of a sudden everytime I pump I have to do it twice! I pump for 15mins...get like 2 tbsp. I wait 30mins to pump again and it all comes out. I massage then before I pump and during. I dont understand why the change. I have been having different breastfeeding issues since birth and everything keeps pointing me to formula but I keep trying to hang on because I really want this for my child.   To double up pumping sessions is ridiculous though....