I'm glad you have a cardiologist appointment coming up. Ruling out any cardiac reason is essential but yes, anxiety is known to cause the spikes you mention in heart rate. https://www.healthline.com/health/anxiety/can-anxiety-cause-heart-palpitations So, if the cardiac work up doesn't net out to be the cause, then absolutely, time to begin working on the mental health piece of this.
No way for us to know. Anxiety doesn't produce the same physiological effects in everyone. If you're having a panic attack, that's one thing, but if it's chronic anxiety it might not affect your heart rate at all. On the other hand, anxious people often check their heart rates and BP constantly, which most people who don't have a heart condition don't do. Our bodies aren't always doing the same things, they vary naturally, so it's the chronic problems that are of most concern. If you're constantly checking your heart rate, it's time to seek therapy if you haven't already. But as to what's going on right now, again, impossible to speculate.