Whether the Master's degree is worth it or not depends upon what you want to do. In my case, I would not have been able to get a job I wanted at all without at least a Master's degree, but you must decide what you want.
Usually, people who give up near the end of a degree end up regretting it, but not always. You must figure out for yourself whether you will regret it or not. If you are not sure, then do not quit, because, as I already said, most people regret it.
It sounds very much like you need a break, and this is normal. If you can manage to spend some time unwinding, that would be great. Doing things that involve exercise are usually good, such as going for a hike in the woods, but you must decide what is going to work for you. If you are not sure, try the hike in the woods.
Make sure you take care of basic things, like eating right and getting enough sleep. If you don't, you won't feel right no matter what you do.
If you had come to me for advice before, I would have told you not to plan your wedding so close to when you are planning to graduate. Both things are stressful, and both are such that you don't need any extra stress from anything else. It is no wonder you are feeling too much pressure. My advice now is to be honest with your fiancee about what is going on, and tell her that your studies do not allow you to be very involved in the wedding decisions at this time. She will either understand this or not. But it is better to find out if she is understanding now than after the wedding. You, of course, must be fine with whatever decisions she makes without you regarding the wedding, so make sure you participate to the extent that it matters to you.
And Mozart was a genius. And Bach:
http://www.amazon.com/Bach-Brandenburg-Concertos-Lamon-Tafelmusik/dp/B000002AQ4/
Sometimes, it is good to listen to soothing music, and other times, it is good to listen to music that thoroughly vents one's emotions. There is nothing like:
http://www.amazon.com/Mozart-Requiem/dp/B0000040W1/
played fairly loudly, in a darkened room, to give way to being depressed. Sometimes, going with an emotion for a while can help get rid of it, instead of trying to sooth it away with gentleness.
On music, you must, once again, decide for yourself what will help you and what will not.