How do I get access to my photos on iPhoto now that it doesn't work with the new software? I need my photos!!!

You may also want to look at this document: https://support.apple.com/en-gb/HT204655

Which version of iPhoto have you been using? Photos can only open libraries from iPhoto 8.0 or newer. Older versions need to be prepared with the iPhoto Library Upgrader Tool (iPhoto Library Upgrader), that does not run on Catalina. This preparation has been done on an earlier system version.

Drag your iPhoto library onto the Photos icon in the Dock (or in the Applications folder) to migrate it from iPhoto to Photos.

Here are some user tips from Photos for Mac  User Tips that will help you in your transition from iPhoto to Photos:

Notes on Migrating an iPhoto Library from iPhoto to Photos for Mac ➙ read first

Moments in Photos are the New Events.

External Editors in Photos Are Here

Photo Editing Extensions for Photos for Mac

Post 9/30/2018 Printing Options for Photos - Apple Community

Ordering Books and Calendars on a Mac that cannot be updated past El Capitan 

Use Project Extensions to order print products in Photos after September 30, 2018 - Apple Support

Create and order print products in Photos with Project Extensions - Apple Support