How do I act when I can’t feel or recall the emotions?

I have issues with blunted emotions and that’s making things difficult for me in my theatre class. I was a big theatre kid pretty much all the way up to high school graduation, so I know how to approximate the emotion through careful planning mimicry of what I observe in others. But without the ability to actually empathize with what I’m doing, even a little bit, I can’t possibly reach the level where I’m acting by REacting, as the saying goes. I used to be able to do the memory trick but it doesn’t really work anymore. I can sit and meditate on a truly emotional moment in my life and terrifying core experiences all I want, and it’ll still just feel like I’m reading about it in a textbook. How do I either push through this mental block or work around it?