Try to understand your kefir. If you pay really close attention, the billions of organisms will transform your food and then transform you.
If kefir over ferments it can separate into whey and curds and thats okay! Even if it does separate, it’s not a bad thing. You can still make it into a smoothie or include it in a recipe. Here are a couple of articles that have all kinds of tips to help you if your kefir is too sour or too thin, or you want to make your kefir creamy again.