Hi and welcome!
Bloating is an emergency that needs to be seen by a vet ASAP!
Please never feed lots of fresh veg to guinea pigs that you do not know whether they and their mothers have ever had any, as in a digestive system not accustomed to them, it can cause bloating or diarrhea.
Take them off any fresh food until at least 48 hours until they are well again and then gradually introduce veg in small bits, no more than one new variety with one meal to slowly build up tolerance.
Bloat, GI Stasis ( No Gut Movement) And Not Eating
Long Term Balanced General And Special Needs Guinea Pig Diets
Please do NOT treat your guinea pigs on spec with low dosed pet shop brands that will not heal. You may need to treat for both mange mites and fungal skin infections. Be aware that either can cause fitting in advanced cases and that you need to be extremely careful when treating.
https://www.theguineapigforum.co.uk...inea-pigs-vet-checks-sexing-parasites-illness.
You'd best open a support thread in our pregnancy section and read up on pregnancy, birth, baby and mother care.
Be aware that about 20% of pregnancies and births go wrong, but that this percentage is going up drastically in freshly rescued pregnant sows in bad state. This is one of the most emotionally taxing sides for all guinea pig rescues.
I am very sorry, but you are in for an extremely steep ride. I sincerely hope that you have the financial resources to afford all the necessary vet care, including being able to pay upfront for a cesarian operation (I've seen US figures of £1000 cited by forum members).
Here is our guide collection; please take the time to read up on all the guides I have linked in.
Pregnancy & Baby Care Guide's
This guide collection includes lists of good standard rescues in several countries you might contact for further advice on treatment or help if it gets too much for you, as well as recommended vets. It also contains guides on how you can settled in and make friends with very skittish piggies. This is especially important for any pregnant sows; the sooner they settle down, the higher their changes for a successful birth. Please be honest with yourself if you have taken on too much; rescuing several neglected and prgnant piggies is not for the faint-hearted and usually requires experience (see the bloating).
Getting Started - New Owners' Most Helpful Guides
Since we have members and enquiries from all over the world, we find it very helpful if you please added your country, state/province or UK county to your details so we can always tailor any advice to what is relevant and available where you are straight away. Click on your username on the top bar, then go to account details and then down to location. This makes it appear with every post you make and saves everybody time. Thank you!