I couldn't tell you because I'm not a vet and I don't want to give you bad advice. Did they work last time?
If they did and you have to wait 'til Monday to see the specialist then, in your place, I would treat as last time just to try to keep the breathing going and the eating up. If piggy is finding hard to breathe then it becomes a choice between eating and breathing and that's not good.
Have you listened to piggy's chest? Sometimes, if there's a wheeze you can here a wheeze or a rattle on the chest too, if you have to wait 'til Monday and you are going to treat with your remaining meds then try to keep a check on the chest sounds. It's quite hard to do too keep piggy still and get your ear against his/her chest but if there's a wheeze in the lungs you'll hear it quite clearly.
If there's no wheeze/rattle in the chest then the infection/outbreak is still in the upper respitory tract which, while still urgent and needs treating, is less worrying than if it were on the chest.
Sorry, also what meds are they? Is it an anti-biotic?