Creating a WP website with a theme and received Error establishing a database co

Hi,
I am new to WP and I installed MAMP on my Mac so that I could create a website locally, everything was working fine, I installed a theme and then I was going through and customising the theme when the site froze and it said the MAMP wasn’t responding, I quite MAMP then reinitialised it and I received the Error establishing a database connection message, nothing has changed as far as I am aware, my local wp_config file info is still the same, I am quite green when it comes to this sort of stuff so any help would be much appreciated.
Thank you