It's maybe too late for you. But I post this and hopefully it will be helpful for someone like you.
If you have 5 days in Ho Chi Minh, you can have some choices. You can take your time to visit Mekong Delta Vietnam to see floating market. Or visit Phu Quoc island which takes 2 nights/3 days. Or you can choose to visit Nha Trang or Da lat. Then you can see you have many options, but just pick one. You don't have much time for all of them.
Hope you had a nice trip.