I would not say he is sick. Are his droppings alright? That sound is what a lot of budgies do when they are just really happy! He loves you!

I have a budgie and he is 4 mounths old and today like never before he is making a crying sound inside him like in this video:http://www.youtube.com/watch?v=zFx31LnRSpk and exactly in 0:03 what does that mean is he sick? does he have a problem?

Thanks