Synchro broken??

I was driving my mustang the other day and decided to do a rolling burnout. When i put it into 2nd i felt like something broke or came loose, its hard to explain. But now when i have my car in second and rev it up to around 4000 rpms theres a, dont wanna say faint but loud enough grindin sound when im accelerating. Also when im in first and im up high RPM range its difficult to switch to 2nd.

I also notice than when i put my car into 4th it feels like its not as firm of a shift and theres something loose making more space in the gear if you know what i mean. ANd i do have a roush short throw shifter if that helps.

What could this be?