Woke up suddenly with a fast heartbeat and hands were shaking is it just anxiety i was really scared it slowed sowed after a few minutes?

I can't tell you: Definatively what occured. However, some people wake during or after a nightmare. They may be anxious, having a panic attack, be disoriented and have physiologic signs of anxiety like breathing rapidly, chest tightness, shaking, rapid heart rate, nausea, etc. These symptoms will usually resolve once the person is fully oriented and can begin calming themself.