If you are studying for a master's degree, Ph.D, MD, or JD, you are going to "graduate school". If you are going to graduate school, you are a "grad student." Speaking casually, all the stuff that a grad student needs to do an be called "grad stuff". So, "grad stuff" could involve studying your subject, doing experiments, teaching undergraduates, and writing your thesis. So, if I ask a grad student, "Hey, do you want to go hang out tonight?" She might say: "Nah, [I have] too much grad stuff." So, it means that the work that she needs to do at graduate school is keeping her busy, and she doesn't have the time to go hang out with me.

Without context it's impossible to say exactly. Possibilities are: Too much work related to graduate school Too much school work to do before a graduation (any level) Too many administrative things to do before graduation Too much planning for graduation event(s) Too many graduate events to attend Too many meetings with people to say goodbye before graduation

Too much grad stuff and I have two jobs.

In what context?