I am nervous = better = I have been nervous

I am nervous recently, since I knew the customers are coming to visit us. same = I have been nervous, since I knew that

My manager and I will pick up them on next Monday. (on not needed)

I am a newcomer in my company only for 4 months, I don't know how to do and what to prepare, my colleague told a lot of things to be aware and it really cause me stress out. ( too many phrases not properly linked with each other. ) Corrections = I don't know what to do, told me a lot of things, and it really caused me, I have been here only for 4 months ( Make it into a separate sentence = better)

I am not good at speaking English, I am so worried that I can't realize customers English. What if I made mistake?
I can't image how my manager's face look like. => can't understand, my manager's face would look like. (You should not worry so much :)

I don't know what topic can I chat with them in dinner time, I really hate this situation. at dinner time. (Maybe you can ask them if they believe in blood type :) or what their blood type is )

I am in a bad mood. (How is your mood now? :)