Eek! substituting almond milk for regular to make buttermilk for my blueberry muffins, is this what it's supposed to look like?

You can substitute a soured non-dairy milk for buttermilk. I've done it many a time; it is the almond milk that is the problem. I've had the best success with unsweetened soy milk and unsweetened rice milk. In turns of mimicking buttermilk, the soy curdles and has the taste, look, and thickness of cultured buttermilk. I know that almond milk has the best taste and probably the best health quotient--but I've found success with soy.

yeah, I don't think you can sub for buttermilk that way. But simply adding some lemon juice to the recipe might do the trick

well, i had to abandon and use a different recipe because i was running out of time. but when i whisked it, it stayed the same consistency. i used a cup of unsweetened vanilla almond milk and 1 TBSP of apple cider vinegar

Most buttermilk is low fat. You rarely see whole fat buttermilk, and the it is only around 4% milk fat, so don't try adding more fat to compensate as suggested above.

Because buttermilk has a lot of fat in it, I would add butter (earthbalance is a great dairy free brand) or canola oil to try to mimic the buttermilk effect.

Did you add vinegar to the almond milk? What happens when you whisk it?