I respond really quickly (like within hours) of taking my meds, and if I forget to take them one day, I can feel it. I get a real low feeling and I know I've forgotten them. (I'm on Zoloft and Wellbutrin)
I'm on the same meds as you. I haven't missed a day with taking meds, but I don't take them the exact same time every day. I've never noticed a dramatic change in my mood for being a few hours off with taking my meds. Whenever I've lowered a dose on my meds, I noticed it takes time (at least a week or more) to notice a dramatic change in my mood.