It looks like you are already the proud owner of a myCloud account. You can find out the username of your account by clicking on "Find your myCloud account".
Alternatively, you can find out the username of your Swisscom login directly on the Swisscom loginscreen.
To do this, proceed as follows:
1. Visit the Swisscom homepage, click on "Login".
2. Select "Forgotten username or password".
3. Select "Forgotten your username "
4. Enter your e-mail address, which is already taken.