my baby has a virus

you need to take her to the doctor.

How long had she been doing this before you went to the doctor?  How long has it continued since you returned?  Does she have a fever along with the diahhrea?

Me, I tend to be overcautious.  If this has been going on for more than three days since her last doctor's visit, go again and insist - INSIST - that they run cultures on her urine/diahhrea and do a throat swab.  They should also check her ears for infection.  Write down EXACTLY how much she's drinking (or time at the breast) and when, because that'll give the doc info for how dehydrated she may be. 

If her temp is in the triple digits, that's something to watch as well.  Don't be afraid to be a pain in the neck at the doctor's - they've got after-hours nurses or staff members answering the phone.  If you don't like what they tell you - screw 'em and go to the ER (but they may make you wait and it'll be miserable for everyone). 

Be aware that there's not a lot you can give babies in terms of medicine.  Antibiotics are great, but not for the common cold or some viruses, and you don't want to give her antibiotics unless she needs them, because she'll only develop an immunity to them which will be a problem later on.  What the hospital CAN do is to put her on a saline drip that can keep her hydrated, and also keep an eye on her temp if she's got a fever.  Chances are, if you go to the ER, they'll see her and they'll run tests, but they won't need to admit her to the actual hospital, unless something is very wrong.

Babies get colds.  Look at it this way: you and me, we've had a lifetime to get used to having colds and building our immunity.  Your daughter's only had a few months!  She'll have a cold and diahrrea and the rest a dozen more times before she's two - and that's a good thing.