I just remodeled my bathroom. I am not an electrician by a long shot although I have done hundreds of receptacles and switches. When wiring gets complicated though it gives me a headache. Here is a drawing of the wiring in my bathroom. I added the light in the upper right hand corner. The rest of the wiring and fixtures already existed. Although the light in the upper left is really a fan but not that that matters. The only other thing I changed was the receptacle to a GFCI. My current problem is the light at the bottom. When I connect the red wire to the switch and turn on the switch it trips the GFCI. When I unhook the red wire then the light in the upper right works fine but that disables the light at the bottom. Everything but that one light works fine without the red wire connected. The GFCI works properly, the fan and the light in the upper right. Where the heck am I supposed to connect the red wire to so that it does not trip the GFCI and works properly?

Thanks for help!