Life after graduation no more stays the same as it used to be before. Don't worry yet. It loosens the extreme pressure you have had gone through in the senior year. Masters here is more like an extension year of bachelors since you are with the same bunch of faces you had been for the past four years.
During this time the routine is somewhat relaxed and number of classes you have to take drops. Still, you have to stay almost full time for thesis purposes. Thesis is the most challenging and daunting yet most interesting and enjoyable hurdle to jump over at this stage. You are going to get hands-on experience and exposure to the realm of research. You will experience practical challenges that you have never read in books and be able to sharpen your mind to troubleshoot and overcome them.
Although there is a short period of time that is quite exhausting when you will be in a rush to get done with the in-courses, the rest of time gives you ample opportunities to also concentrate on your extra-curricular interests or get prepared for higher studies. This is the time you feel the transition that is going to take place in your life - from student life to career. Masters is the preparation phase for this level up.