Hearing Heartbeat in Ears

I notice it a lot when I bend over to pick up something or when I get up or when I lay on my stomach. I clench my teeth almost every night, and I think that could be making it worse, and I have really bad allergies to the mold problem in my apartment, which make my ears extremely itchy at times. Today, it has been making me very anxious, and I almost feel like I am about to have a panic attack.

This happens to me when I stand up/sit down too fast