Sorry to hear you've been having ongoing problems, it does seem to be getting better though
well done for your hard work and dedication
It sounds like you're dealing with gas bloat from the posts above, keep going with the medications you've been prescribed from the vet & the massaging.
I'm not sure on the olive oil so I can't recommend that.
I know a few members have used gripe water with good results, like you suggested earlier (I don't know if you have any supermarkets nearby, but asda&tesco sell gripe water in the UK, I've searched wallmart & Kroger in the USA & came up with these
Gripe water
https://www.kroger.com/search?query=Gripe water&searchType=natural
If they're any help?)
Gripe water is usually found in the baby aisles of a supermarket or in a general pharmacy.
The gripe water works by breaking down the gas into little bubbles & dispersing them more easily.
With Infacol in the UK (possibly similar to the simethicone in the USA) the bubbles join together making a big bubble, for the baby to burp out easily - Guineas aren't really able to do this, so the gas stays in place like trapped wind, making it painful & reducing appetite.
For the moment feed only dry foods such as nuggets, with access to hay & water at all times. In addition keep going with the recovery food to keep her gut moving. As suggested above.
I think with the Zantac it helps to move food through the guts, so pushing through any food to be digested& out the other end, filling the digestive system with a constant supply of food instead of air/gas bubbles that cause problems (however I'm not a health/medical expert so I'm not 100% on this).
Good luck & healing vibes being sent your way for a full & speedy recovery.
Keep up the massaging
Xx
Ps it's a Bank Holiday in the UK today so many members may be having a lie in zzz
Xx