At 0900 i had my PT session which lasted 70 mins, i have told my instructor that i want to be worked hard as i need to lose a lot of weight, and boy did he put me through it. I then thought i'd do the runs down by the canal where i live as i prefer running outside. Well the warm up was good, the first 3 minute run was ok, the first 5 min run was a struggle, it was when i came to do the second 3 min run that i had problems, i barely got through the run but jogged so slow i would have been better walking. The second 5 min run was a disaster, i hit the wall almost immediately, this caused me to go very light headed and nauseus and i almost toppled into the canal
It was nearly 15 mins before i managed to get my breathe back and compose myself. I think the moral of the story is don't try to be a smart a rse and push myself to the limit twice inside 2 hours 
That's great determination though – well done!