First of all Dylan... there is a misguided rumor that only girls cry. That is just not true. I cry all of the time when I teach classes! 
Someone that is touch with their emotions doesn't have too many "self-control barriers" to go through. Crying in turn becomes easier.
What is crying? It is your body responding to an intense feeling. If you are training hard without concern for your own well-being... your body and mind are going to react. Sometimes in ways that you do not expect.
Dr. Colby Wang and I do not see eye to eye at times. I am a student of experience and he is a student of statistics. That is the difference between Philosophy and Psychology. Besides... he loves to prescribe medication to anyone. Drug Dealer!! 
Oh Colby... you know I like and respect you. But jeesh... not everyone needs to be on medication. Only those without choice should be prescribed another means to cope with their issues. We all have them to one degree or another.
You should not feel inadequate because you are struggling with your training. That is the essence of ALL success... PAIN! If it was easy... everyone would do it and we would not have the term "Excellence".
I have, personally, experienced what you may be going through. When Sigung Chiang died so suddenly... anything would set me off crying. I still do have issues with this but it is getting better. I become extremely sentimental around the month of June every year. Sigung Chiang died on 21 June 1994 so it is understandable.
When I was younger... the only thing I knew how to do was cry. The extreme training that Sifu put everyone through was difficult for me. It was very trying for longer than I care to admit. However, when I finally broke through my limitations... everything became possible!
Keep your chin up and do not allow your limitations to control your efforts. Remember... "Success is not measured in our achievements, but in how we deal with failure". You will fail more often than you will succeed. Do not become a statistic. Become a student of Kung Fu and a Master of yourself!
