Ive been in a relationship where there were times when we wouldnt talk much. I would search myself for something to say and just end up talkin rubbish or stayin quiet.

Like you im quite shy.

It would worry me cos id think 'shit, shes gonna think im boring' or whatever. And i have to admit she probly did think this at the end. It never worked out and I was heartbroken but now i realise that it jus wasnt working and i wasnt havin much fun sitting there in silence anyway.
Maybe this is isnt the case with you guys...but be prepared if it is and dont worry about it, if you cant think of anything to say then maybe this guy isnt right for you.
Quietness is my biggest problem.