Bunch of workflows just got stuck in the production... may be close to 300!

The stuck workflows doesnot have error statuses, it is just stuck. Does'nt come up in ST22 or whatever. I need these going... Should I restart them? Well these happened exactly at the same time when the production environment was very slow yesterday... Please let me know the best way to solve.. Appreciate your help in advance...

Thanks,

Sukumar.