Piggie company and the story

Question
We started with two piggies, both that we thought were females, until after our one female gave birth (she was pregnant when we bought her), and then we noticed our other female trying to mate, when oops, it wasn't a female but a male.

We took him back to the store and got store credit.  

With our female, she had 3 babies and only one survived.  We kept it in hopes that it would be a female.  Well, today I was able to sex it and geez, it's a male.  

So, my question, we will be selling it to the store, should we get another female, or do you think just one piggie will be ok alone without another one?  We aren't oppossed to getting another, but if we don't have too, we'd rather not.  

Also, I'm pregnant, like cat poop, do Guinea pigs carry anything that I should worry about?  

Thanks.  

Answer
You do not have to get another pig, most guinea pigs do just fine on their own despite what a lot of pet stores might tell you. I actually have some guinea pigs that will not get along with another one. Guinea pigs are a lot like humans, and they do not have or get anything contagious other than what a person might bring into the house like a cold or pneumonia, so you shouldn't have to worry. I would however avoid cleaning a really dirty guinea pig cage because guinea pig urine does have small amounts of ammonia in it, which could cause nausea.
Brittany