I Am 20 Years Old. I Was Diagnosed With Have

I am 20 years old. I was diagnosed with have anxiety. And sometimes panic attacks.at times i have palpitations. I feel my heart beating very fast then it stopped for a second,then started beating a bit again.other times my heart is beating fast for no reason have no history of heart problems or anything. Can u tell me what is going on? Or is it my anxiety that I causing this?