For days I have been having problems sleeping at night and I haven't been able to wake up early. Tonight I could sleep very well so I woke up early and I'm really happy about that.

Hi Ana, Hristina already corrected this for you. All I really want to add to her correction is you should consider paying attention to your tenses in subsequent writing excercises. Generally speaking, unless the meaning of the sentence indicates otherwise, you need to use the same parallel structure, the same tense, to show that two or more ideas have the same level of importance, show a sequence of events, or follow a certain pattern. Take, for example, this first part: For days, I have been having problems sleeping at night and I haven't been able to wake up early. You're expressing two ideas regarding your sleeping patterns for days: you have problems sleeping and thus have not been able to wake up early. For this reason, you must use the same tense to maintain this parallel sentence structure. There is nothing here to indicate a need for a tense change. Hope this helps! Happy learning!

I have been having problems sleeping at night for days and I haven’t been able to wake up early. However, today I did wake up early and I'm really happy about it because it could mean I’ll sleep very well tonight.