If the toothbrush itself is still vibrating as it always did then that bit's fine. I'd suggest you've either bought 'soft' brushes or inferior fake brushes. I'm always horrified at the cost of replacement brushes, really expensive for Oral B anyway.
No the toothbrush is finished. Sista gave me a new one OralB Braun - I went Happy Days - omg - no way could I use it - too powerful and sensation not good. I will order another Philips.