Helbound, you took damage from guns. Since we don't know what his FE saw, we can't tell if he took serious damage (flight surfaces, engine oil, PW, etc), or if he just made enough contact to knock off the tailwheel or something minor.
If you received the "Soandso collided with you message", but did not receive a "You have collided" message, and took damage, you took that damage from weapons, not from the collision. He, in this instance, would have taken damage from the collision, but not necessarily serious damage.
Sometimes you'll lose a wing when you ram, sometimes something useless like flaps or landing gear, but only the guy whose system registers the collision takes damage from it. Mind you, there are situations in which both PCs register a collision (normally one right after the other), and in these instances both planes will receive damage, since both FEs decide that the player occupied the space currently filled with the other guy's plane, but this doesn't sound like what happened in your case.
Clear as mud?