Have you experienced that kind of feeling from which you felt so down and like no one is there for you? Don't worry. You're not alone. There were several days of my life, just like as yours, that I have totally experienced this kind of situation. 
Being so down in a most struggling days of your life really affect your own physical, social, and mental system. It seems that everything around you went downhill. It's like starting a project over and over again and the continuous effort to finish it gone so wasted. Well, it's not only you who experienced this. Because all of us had been in the same scenario. 
Don't complain once we fail. Think of it. God has given us these problems and challenges in life in order for us to grow - into someone who is capable of change. It's okay to be weak for as long as you still find that reasons to compose yourself and gain your strength. It's okay to cry and let out all the emotions needed to be alright again. Its okay to be at your weakest spot. Remember that lessons are learned in every downfall. 
For every struggle, remember that there's no way up but starting yourself from the bottom. So be grateful for you are blessed enough with God in your side.