Hi &welcome

Sounds like a respiratory infection as the others have said.
A vet visit is needed I'm afraid
If you get the vet just to check her eye for a foreign object too. She may have a bit of hay or something in it making her squint if its one eye. Although the respiratory infection can make their eyes gloopy too.
Not sure if you are aware but normally Guineas secrete a white, milky fluid to wash their eyes with which is normal,sometimes they get a build up of this &it forms 'sleepy dust', but if its gloopy& slightly yellowish tinged its probably because of the infection.
It might be as well to take another guinea with her to the vets for a 'paw holding' friend as support.
As you have only had her two weeks I would see if you can get her vet treatment paid for from wherever you got her from.
If she was a shop bought guinea, copy &take the receipts to claim a refund. As they haven't sold you a 100% healthy animal.
(also take a copy of the receipt guinea that you bought to prove how long ago you bought her from there too)
Try putting a bowl of steaming water just outside her hutch or cage so that it will help loosen the mucus to ease her breathing.
you can put a few drops of olbas oil in it or on a cloth nearby (out of piggys reach) this will also help her breath more easily.
Make sure her bedding isn't dusty, (eg, sawdust) or mouldy hay etc. This can cause respiratory issues also try not to use strong toiletries/perfumes/air fresheners or aerosols In their room if indoors as this can irritate the respiratory system too.
Unfortunately the first month at home is usually when piggies are most prone to opportunistic illnesses.
They are stressed due to the move, new surroundings, new owners &sometimes other pets being thrown into the mix too.
This is a lot for a new guinea to cope with especially at a young age &their immune system is still low.
Its good that she's eating, monitor her weight daily whilst she is ill &make sure she is gaining/maintaining weight well with a steady flow of healthy poops on the output side.
Good luck with the vet visit &keep us updated. Ps photos are always welcome,especially mini pigs
Speedy recovery little one. Xx