8 year old boy - very nervous

Dear Dr Shinhar, this is third time I'm writing this e-mail, hope to get a reply this time. My son is 8 years old, lovely boy, kind heart, good at school, though a bit baby-is, immature. Main problem is he is very worried AND nervous, about anything - to be late for school, not to do his homework, to bring the wrong book, to miss train/flight/bus, to lose our way (when driving all family together), not to be able to fall asleep, etc etc. Even the slightest deviation from his routine causes him stress. he constantly bites his sleeves AND shirt colar. He is not care-free as a child should be. Sandwich boy between 10 years old sister (manipulates him constantly) AND 21 months old baby, who takes all my time Please give me advise how to behave with him, so he doesn't grow up neurotic. many thanks your help.

Dr.Shinhar, thank you very much for your reassurance. It does make me feel better.