Both my throttle AND clutch cable seemed to have stretched simultaneously recently. Both the pedals were sitting lower down than normal and just didnt feel right. I have taken up the slack and things seem ok.

My question is:
should I be concerned? It seems odd that both would stretch simultaneously like that. I also remember hearing distinct 'thunks' on both pedals, followed by pedal sitting lower on the floor

Welds holding the tubes in the tunnel broken?

Yogie

Check your 4 engine bolts are tight

Maybe the pedals have moved.