I have developed a web application and would like to make it open source.
The application is a task manager. You can use it online for free after you sign up.
For me, it is not easy to create a license for it from scratch. So I was hoping I can use an existing one (i.e.: GPL, Creative Commons).

For my application, what I would like is:
_ the user may download the source code of the software
_ the user may modify the source code of the software to suit their need
_ the user can't redistribute the software
_ the copyright note and the link to the origanal website must not be removed
_ you can install the software on your server for your personal use (max 5 users). For more than 5 users, you need a written permission.
_ the user will automatically grant me the non-exclusive right on any modification of the code

What I do not want is:
_ people start a business with my code and become a competitor
_ people start forking from my project

Does anybody know a license that can tick all the boxes?

Second question.
If I find a license that ticks almost all the boxes, can I link to it but state some additional clauses?

Thanks,
Daniele