Abnormal noises. Should I be worried?

i was driving my bike (K3 Sv650s) today along the motorway today and noticed that it was making small pops sorta missfire noises, but i kept on driving. When i stopped it was turned off for about 30mins, then when i started it the idle kept dropping down to just below 1000rpm, then it would correct itself back up to its normal about 1400rpm then drop again.

Again i kept driving and noticed it being jerky trying to hold a steady speed, then on the motorway sliproad coming off, as soon as i pulled the clutch in to stop it cut out, i started it again, it cut out, then the second time i started it it let out quite a loud backfire and stopped again. I then sat at the side of the road for about 5mins before tryin it again, when i switched it on after this it seemed to be ok, but i went straight to the petrol station n filled it up with super unleaded, and it has been fine for another 30miles or so since then

a couple of people have said to me that it may have just been bad petrol, but i had drove it for maybe 30-50 miles before i noticed it coughing.

is it likely to be just bad petrol or should i get it checked out incase its sumfin major?? Ive owned the bike for 6 months now n have drove it over 4000 miles in that time n this is the first time its done anything