Sounds like a full-blown panic attack. I've had that before. Felt like I was gonna die! Sounds like the fire alarm caught you off guard and your body when into fight or flight mode real bad. For panic attacks I have a few tricks: CBD oils, splash cold water, tell myself "Not today!" (and mean it, you have no time for this BS), lay down, deep breathing. If all else fails, YouTube has a million soothing sounds for anxiety.
If it doesn't go away, you should see a doc.