Anxiety and stress affecting my health

I went to the doctor the other day and was told I had abnormally high blood pressure for my age (18). And also that my heart rate was a little fast. I have really bad anxiety and tend to overthink and worry about everything. My relationship with my bf has been rocky lately, my parents stress me out, and I’m moving to another state by myself in a couple weeks. My doctor told me to watch my blood pressure for the next few weeks and come back if it hasn’t changed. But now knowing that it’s high, I’m stressed about it. What can I do to reduce stress and anxiety + also lower my blood pressure so I don’t give myself a stroke or worse?