Sherin this all still really fresh. Just keep yourself busy and talk out everything with YOUR family and YOUR friends. It will take some time, but it will get better.
I am about 2.5 weeks in to the break-up of my 3.5 year relationship with the love of my life. Yea, I still think about her from TIME to TIME, but not ALL the time. I have good days and bad days, but I manage to get through them/ You need to find something that distracts you from thinking about him. Learn to laugh and have a good time with friends, that really helps. Make plans to go out with people and HAVE FUN. Don't sit around alone and think. Also post here as much as you want top vent or ask questions, we are here for you.
Like you I had many about questions on why she ended it with me. I found after a couple of days I was able to settle down and reflect back on signs I have missed, my feelings about things and found that neither of us were as happy as we were when we first started going out. Things that happen while we were together wore down our relationship...
I think once you look back with a clear and mostly settled mind you will be able to answer many of the questions you have.
Also, if you tired of waking up in the middle of the night, seriously think about joining a gym, taking up martial arts, or some other physical activity that will wear you out. You will find that it is much easier to sleep through the night.
Also those dreams you may be having will pass or not be as intense as they maybe now...
Just keep moving forward, and don't dwell in the past. YOU CAN DO THIS!!