Touchy are'nt they!
Seems you may have made a simple slip connecting a switched live to live feed
One of the reds may be a red sleeved black or be extended from a joint in the ceiling void
This is the common method of using twin and earth cable to take live feed to your switch via red then return via black to the light unit
The third red is forms a junction or loop out from the permanent live to the next room/light unit in the circuit
Thats my story and i'm sticking to it
Ask again if you need more help
Best regards
Asanewt, January 2009