Only see home page and can't login to WordPress on my localhost site

Hi guys. I am building my WordPress site locally using AMPPS and had it all working beautifully. I forwarded the site using ForwardHQ and changed the site URL so I could share it with a client. When I switched the site URL back to my local site, suddenly everything seemed to go wrong. I couldn’t login to WordPress any more. I put my localhost/mysite address into the config.php file to reset the site URL back to my localhost. I edited the option in myphpadmin.

Getting the site URL back to normal doesn’t seem to be the problem. I can only access the home page and all the other pages give me: “Not Found The requested URL was not found on this server.” and when I try to go to localhost/mysite/wp-admin, I get “This webpage is not available” error. I want to change the permalinks setting to see if that would fix it but I can’t get into my admin. I am really stressing about this because it’s for a client. Any help would be much appreciated. Thanks in advance!!