If you have test anxiety:
Remember everyone takes test and it completely normal to be nervous! It's even been shown that having a little nerves can help you perform better!
Second, just prepare yourself. Don't cram the night before, but set up a manageable study schedule. Try visualizing yourself taking the test and get a good night sleep.
Lastly, go into class and just focus on the task at hand. Don't stress over it or discuss it with others, just go in and take you're test.
If you are stressing over finding time to study:
Try planning ahead and creating an easy study schedule. Beyond that it's just a matter of finding effective time saving study tricks. One of my favorites is the flashcard app- take the 10-15 minutes to make your flashcards on this app and then squeeze in study time anywhere you have your phone with you! Also, it sounds silly, but make recording of important information and listen to them while you're doing something else. It will help reinforce the information and won't take any extra time!
If your worried about your grade:
First, know that your grade DOES NOT define you. Everyone, even Albert Einstein, has failed sometime in their life. It doesn't mean ANYTHING. And one bad grade won't wreck your overall grade. You can always make it up! Just make sure you study hard and you will do fine! Maybe even try some of the tricks above to aide in your studying skills or calm yourself down.
Keep it up!!