Good luck in your Ph.D. program. I know I do not know you, however, I just passed this blog today online, and I thought I would add my input. I am just about finished with my first year, and I will say it has been a journey. Fortunately for me my family and friends are huge support. I will say this, one of my mentors told me to give up a lot of the pleasures of life and strictly devote my life to my PhD. Trust me, don’t fully give up on the pleasures of life, every now and then I will go out on the lake and go fishing on my boat, and have a beer.
I currently have a 3.6 GPA with 4 A's and 2 B's. I will say this, professors who give B's because you deserve them. It does sound to me that the original poster is a bit immature. I hope by now you should be just now completing your first year or nearing it; you have learned to settle down and take the advice your mentors have given you. Grades matter, but then again they do not really matter, the Ph.D. program is in three phases; course work, comps, and dissertation. If you need a minimum of 3.0 to get through your course work, then ensure you do that. However, in the long run, you will