Not to be pushy, but have you checked out Agile Retrospectives: Making Good Teams Great! ? It includes lots of ideas for planning and leading retrospectives that get benefits for the team, including choosing a different focus for each retrospective.
In the book, Esther and I discuss how to make decisions about duration, focus and location for retrospectives--all make a difference. How many people are on your team? If you have a 3-person team of only developers that pair program and talk to each other frequently during the week, you may not need retrospectives so frequently. OTOH, if you have a ≥7-person cross-functional team you almost certainly will benefit from a retrospective every Sprint.
With one week Sprints (good for you, btw), plan your retrospective for ≥60≤90 minutes. You could choose to have a rotating retrospective focus. e.g., sprint 1 - retro on engineering practices, sprint 2 - retro on interaction & working relationship with PO/customer, sprint 3 - retro on work process practices, sprint 4 - retro on teamwork & working relationships, then start the cycle again at sprint 5, etc. Unless something extraordinary comes up that week, in which case, that becomes your retrospective focus. Not every retrospective needs to focus on unpleasant challenges, difficulties or setbacks. Use some retrospectives to explore the puzzles or mysteries, and some to celebrate the challenge of building on/expanding/extending accomplishments.
Remember to have an improvement action or experiment deliverable for every retrospective.
For more resources, I have posted new retrospective activities on my blog to add to the ones in the book.