sophie,
All your sentences are correct except this one:
"Uyumak istedim ama isteyemedim"

Yes, perfectly done sophie.

Your last sentence provides a typical verb conjugation and a good example for beginners. So to help beginners let me show how sophie has conjugated the verb:

uyu + y + a + ma + dı + m : I could not sleep

uyu : verb stem (sleep)
y : buffer letter preventing two vowels next to each other
a : unabilitative suffix
ma : negative suffix
dı : past tense suffix
m : first person personal suffix

Notice that a negative suffix always follows the unabilitative suffix.