A funny thing I have noticed about great strength is that it tends to hide, even by it's possessor some times. But you can recognize it by it's results.

You truly do not know how strong you are or exactly what you can accomplish, until your back is against the wall and you have no other choice but to be strong. 
There are many documented incidents of seemingly frail people who have exhibited inhuman strength in the face of a dire situation. 
Heroic acts such as someone lifting a car off of someone to save his life, are well-known and not as rare as you may think.

Don't sell yourself short. 
Believe that you are strong and powerful. 

Train your mind not to accept weakness or limitations. And then, train to ensure that you are as prepared as possible to respond to whatever life may send your way. 

Ban the word "can't" from your vocabulary. 

You must train your mind and spirit, as well as your body. Napoleon Hill stated, 
“Whatever the mind can conceive and believe, it can achieve.” 

Never give up and never give in. 

ps/smoh