Can you bonk on a three mile run?

Ok so the good news is that I had none of the niggling aches and twinges that I experienced yesterday. I did feel the tightness in my left hamstring but it was very short lived. Also I felt it about a half mile earlier than before but that may very well be that I did my first significant hills since the injury. The not so good news is that we (Maggi and I) had to walk most of the last mile. I suddenly got very weak. Not dizzy just no gas left in the tank. It felt like I was going to fall down. My legs were wobbly. After thinking about all the possibilities I think it is likely a combination of the humidity and lack of calories. I've been realy watching my food intake this week. Trying to get back to more sensible eating. More fruits and vegetables smaller portions in general. What I forgot is that I usually have something to eat in the evening by 6 pm. We didn't start our run until 5:45. Ididn't go hime between getting off work at 4 and our run. I should have brought an extra banana or an apple or something to hold me over. I hydrated well during the day for a normal day but the extra humidity probably called for something extra. A banana would have solved both issues I think. If it's not one thing it's another.