Were you using like fresh pine like from a lumber mill or wood chipper? or shavings sold as bedding? Shavings sold as animal bedding are going to be kiln dried (or "heat dried"), otherwise the bags of shavings would get moldy before they sold as well as be sticky from the sap. The only time you are going to find non dried pine in most places in the world would be landscaping mulch. The biggest problem with fresh pine is the sap, which is high in sugar, and the oils in it that are toxic and cause issues like respiratory issues, liver failure, and skin irritation. If you actually used fresh pine then you do need to get to the vet to see if anything can be done.
However, even kiln dried pine can cause respiratory issues if it's dusty though, and being allergic to it is not uncommon. Also, not being able to breath well or smell because of being stuffed up can affect appetite. If it's just a issue from the dust then removing the shavings and replacing with fleece or non dusty shavings should fix the problem.