On Feeling worse while Trying

Writing this after finishing my 10k run. After i finished my 8k, my legs couldn't support my upper body, I still kept on pushing and finished 10k. At the moment, it felt like, I i run for few more km, i would be dead. But in hindisght, i felt that i should have pushed myself more. But nevertheless, Felt good that i finished 10k, but felt bad that i took a lot of time and also realized that my legs are very weak and I need to work on them.