Anita, when WX5 updated from v17 it offered to make a copy of your project. Assuming you allowed it to do so you can still work on the v17 project with version 17. 

For reasons I do not understand Incomedia overwrote and removed v17 when v2019 installed (they did the same from v16->v17), but if you now go to your profile (top right this page) you can select download, select v17 and download it. When you have re-installed it you will have BOTH versions again available.

You can continue to work on your v17 project for as long as you wish, although you may wish to turn off "check for updates" when running the program.

If per chance you did not allow WX5 to copy your project, you can still proceed by importing an iwzip (step5 export, export project) created in v17.