[JoeyP]

Aww ... poor little guy sounds like he's a very nervous little pup

If he's submissive peeing and shaking it's likely not anything physical
pass it by your vet but I'm assuming he's had his shots and everything is going ok

What You can do to help him and yourself is first understand where he's coming from
Everything seems like a threat
So loud noises
sudden movements people lunging at him and towering over him are going to make him cower

When you call him or come to him don't reach out to grab him
let him come to you
if you want to pick him up squat down before you reach for him
talk to him in sootheing tones

a lot of this he will grow out of but if you work with him it won't be as much of a nuisance

also when people come to you house tell them not to chase or lunge for him let him come to them