Should Bright Yellow Fluid Draining Out Of Nostril Be Considered Serious?

I'm a 40 year old female, healthy, although I am overweight, prediabetic, and on medication for a rapid heart beat. I was diagnosed with a bad sinus infection last week and given a course of zithromax (finished it yesterday) other than a lingering sore throat and some ear pressure/pain i'm improving. Today while crocheting with my head bent forward my nose started to drain from the left nostril a clear but to my shock a bright yellow watery fluid (think a highlighter yellow) is this just ear/sinus fluid draining as I get better or should I be concerned of something more serious like csf fluid leakage (no head trama suffered) I guess what I'm asking is should I go to the er or ignore it?