We had this problem with my Shetland Sheepdog, Seamus.
We helped him get over it by always approaching him at his level. Sometimes, when you approach the dog and you are towering over them, they get firghtened and pee. So, making sure to squat at their level helps a lot.
Secondly, when we knew people were coming over, we made sure Seamus peed shortly before the people came. Then, when the people came, we asked them to not act overlly happy and loud when they came inside so Seamus would not get too excited OR
frightened (depending on whether the person was friend or stranger) and pee while trying to greet them. It is important that everyone keeps a calm attitude when they first come in.
And, NEVER, EVER, EVER scold them for submissive peeing! It might sometimes be irritating, but pretend like it never happened! When the dog settles down and is resting somewhere, just go and quietly clean up the mess. Scolding them for it WILL make it worse.
To help build your dog's confidence, praise them a lot. Training them is a great
way to build confidence. Praise, praise, praise and lots of loving and cuddling on the side!
Since your dog is so submissive right now, it would be best NOT to scold them. Try positive reinforcement and distraction. If you must scold them (and sometimes we all must), a simple sharp "No!" or "Drop it!" (whichever word is appropriate) should suffice. Don't yell, but make your voice sound almost like a growl and a little louder than the volume you would typically use speaking to your dog.
I think if you do these things, you'll gradually see some improvement as time goes on.
Seamus got over his problem when he was around 10-11 months old. Occassionally, he still does some submissive peeing, but it's usually when something scares him.
Good luck, and keep us updated on your little baby's progress!