In my opinion, these are your options:
1. "I didn �t sleep at all this week." = It �s the end of the week (for example, Friday afternoon) when you say this. There is no remaining time in the week for you to catch up on your sleep.
2. "I haven �t slept this week." = It �s the middle or near the end of the week (say, Thursday), but the week has not ended, so you could, in fact, still get some sleep before it ends.
3. If you are at the doctor �s office and she is asking you about your sleep patterns, you can say "This past week I didn �t sleep." This may mean that you still aren �t sleeping well or at all, but it �s a particular set time that you are mentioning. However, as a native speaker, I wouldn �t normally mention this in a casual conversation about sleep.
Hope this helps.
Have a good evening.
Zoe Morosini