Sentence 1: Yesterday I was working very hard at work. 
 Sentence 3: I worked right through my lunch break 
 Sentence 4:  When I realized that, I was so hungry I couldn't work anymore 
 Sentence 5:  I asked my boss to take a break and he said yes 
 Option 1: I was working so hard that I had lost track of time but will never take a break again. 
 Option 2: I was working so hard that I had lost track of time.