Hi
HUGS
I am very sorry about the bad news. They are hard to take in when it is much worse than you expected, especially when you thought you knew what was going on.
You are always entitled to seek a second opinion; especially with a serious diagnosis like the one you have got.
Here is our list of recommended vets:
Recommended Guinea Pig Vets
What we cannot do is tell youwhether your piggy has got indeed bloat or not, or whether any bloating - if there is any - is primary or a secondary complication to another underlying issue. This can only be done by a vet in a hands-on examination and with any further diagnostics they may need. We do not support home treating on spec with DIY medication because it can easily make your piggy's suffering much worse and could be fatal if you got the wrong end of the stick.
Gassing usually shows up very clearly on an x-ray as a milky area and should be pretty easy to diagnose for any vet. It will look very different when compared to a cancerous internal mass, which is sadly not all that uncommon in older guinea pigs. Please be aware that the bad news could be confirmed by another vet.
Please step in with feeding support asap. The funny poos are caused by your piggy not eating enough because of pain - poos reflect how much a piggy has eaten a day or two before. Hence her feeling skinny as well.
Our medicating and support feeding guide takes you through the whole process with pictures and videos. Please weigh her daily on your kitchen scales first thing in the morning for instant feedback of her food intake and then step in with the appropriate level of feeding support. The guide also contains a chapter on what you can do when you need to improvise.
All About Syringe Feeding and Medicating Guinea Pigs with Videos and Pictures
PS: Is the meloxaid 0.5 mg (cat strength) or 1.5 mg (dog strength) concentration? In either case your prescribed dosage is very low. Meloxaid (active ingredient: meloxicam) is another generic brand name for metacam.