What to do when someone does not respond to your email? So, I am struggling with one of my upper division math class(Partial differential equations). I contacted a close family friend to see if he can help me or if he knows anybody that can tutor me because he is a math professor at a college. Long story short, a grad student emailed me and said he is willing to help me because he had the same professor with same class, but has not done that class for a while but is willing to catch on after reading the notes. 

Then, he asked to email him the course topics and I emailed it to him. Two days later no respond. I am frustrated because I am really having a hard time in that class and recently failed a quiz, and I am stuck on the next homework assigned and have another quiz this week. I don't want to go to my professor for help because he will ask why I did bad on the quiz, which I feel embarrassed  and I had been going to his office hours for help before quizzes and homework. So, what do you do in this position?
First, forget your embarrassment and go see your professor for help. That is his job. If he asks why you did poorly, give him the most honest answer you can and see if he can provide some suggestions to get over the block. Your difficult with PDE is pretty common as it takes a new way of looking at things after calculus. 

As for the tutor, two days is very little time to make initial contact. So, you can ask again, in email, about current topics. But once you do make contact it may go more smoothly. But grad students are pretty busy. 

But, I also urge caution with any tutor. Make sure that they don't give you so much help with things that  you don't actually learn yourself. The best thing they can do is give you some exercises and watch as you solve them, with you expressing your thoughts on what to do verbally. The best tutor will give you only minimal hints when you get stuck, and not show you how to approach every problem.