1. Listen to a calm playlist.
2. Watch some yoga relaxation videos.
3. Own your space.
Lay on the floor in a place you feel comfortable where you can stretch out, put some headphones in, play some of your favorite music, and sing along. This is more of a cheer-up than relax tip, but sometimes that's what you need. A bit more happy than calm.
4. Have some reading fun.
Find some old picture books and start reading. It's got a nostalgic, calming effect to just lose yourself in the childhood things you love; plus, usually the art and stories are pretty inspiring.
5. Sketch it out.
If you're artistically inclined, or you're comfortable enough with art that it doesn't frustrate you, then do some sketching. Find a comfortable spot and look for something to focus on. It could be a doorknob, a sock on the floor, whatever. But be sure to also tell yourself that this is for fun. It's not a challenge to prove yourself. The quality of the sketch doesn't matter, it's just for the concentration.
Let me know what else you do to relax and de-stress. And, of course, my top recommendation would be to see your doctor and discuss the best way to deal with your anxiety.