itunes deleted my apps from my ipodtouch!

Maybe someone will be able to help. So I wanted to put some pictures on my new ipod touch with itunes and everything was OK until itunes started to synch all my apps and he deleted them from my ipod touch. Now they are on my itunes but I cannot put them back on my ipod touch. I had the lonely planet book for Washington that I bought today and it doesn't want to go back on my ipod. I don't know what to do? Can anyone tell me what happened? I am new to the ipod touch world. I had a nano and I managed my songs manually so I didn't touch anything with the apps because I wanted to do it manually. I don't know what happened.

Anyone? Thank you in advance!