Panic attack in first lucid? Need help to explain what happened

[Skullx]

Hello all guys, so this is my first message here I've heard about lucid dreaming a month ago maybe just randomly, talking to other people I realized in my country the lucid dreaming thing seems a lot less known than in the US. I read stuff here and there about lucid dreaming, but never really got interested to it. But last night, something different happened. I was having a very plain dream. I was in a car, you know, a big car like the ones you have in the US, with your horrible automatic drive I was sort of parked, and I had to back out but I was surrounded by many other cars, so doing it was damn difficult, and for some reason the automatic drive, which in reality is easier to use than manual, in that dream was terribly hard to use. I was very afraid of scratching the car while backing out, until I suddently told myself "who cares, this is a dream"! Now, normally in a situation like this I wound just have woken up, but not this time. 2 seconds later I realized what I had just told myself and thought "woha! I am having a lucid dream! I want to stay in!". I'm totally sure I would have never thought something like this if I hadn't read about lucid dreaming a month ago. I was very excited. Sadly, the excitement lasted for one second. After that, I started to feel my body in pain. I mean, I was still in the car, but I could feel my body - my REAL body - being in my bed with all muscles in tension, pain under my skin over whole body, crazy fast heartbeat.. This was not my body in the dream. I was in the dream but I could feel my body in the bed. It's hard to explain. I just thought "I want to get out! I want to get out! I want to get out! I want to get out! I want to get out! I want to get out!", but I could not, I was still sit in that damn car... I was like damn TRAPPED INSIDE THE DREAM while my body in reality was calling for help. I don't know how long it lasted, a few seconds I guess, then I finally woke up. I don't remember exactly how the transition was, like the dream faded away and the real world built up around me. I'm quite sure my eyes were already open when I woke up. My body was still all rigid and in panic, but this went away soon. So guys, that's all. I'd just like someone to explain me what happened, and how to remain inside a dream next time something like this happens. Thank you all .)