I have a similar set up to you a 128GB SSd with 2 x 1TB HDDs. All my three PC's have an SSD as a boot and program drive, two have 18Gb SSD's and the third the HTPC has a smaller 60Gb SSD.
A 128GB SSD should be more than enough for your operating system and programs provided that your SSD has been set up correctly at the beginning.
The first thing you must do is move all the My (Video,Picture,Documents,Music)folders to a bigger drive, this should have been done if you bought the PC with the SSD and the two bigger drives already installed. Instructions on how to move them.
Once that is done everything you add to these folders will automatically stored in these folders in there new location.
All your programs can be installed on the C drive (SSD) as for the Big-Fish manager this can also be installed there but when you installed the manager it did give you the option to install the games on another drive, this could be found under the Advanced button. But you can either change the game install location by going to Manager-Options-Downloads-and then change the location to one of your bigger drives. Create a folder there and call it Bigfish or something. Once that is done your games will install on the bigger drive rather than the SSD.
But as I suspect that you have been installing your big-Fish games to the default C drive,the SSD, it might be necessary to uninstall the manager,then reinstall but this time make sure you change the game install location folder.
MSE and Chrome are fine on the SSD it is your Big-Fish games that are eating your space I suspect.