If it's only on Infill it sounds like it's the filings that's affecting you, I'm assuming you soak your toe gel polish but file nails for infill so possibly the gel top coat/design...could you wear gloves while doing infills? Do you use an extractor fan?
Also, is your L&P ratio perfect? As if not, that is uncured product which is not good especially when filling through it when an infill comes around. Same with gel, if you're not using the correct brand of lamp, again there could be uncured product which might be causing the problems
I wouldn't buy a whole new system untill I'd troubleshooted everything but I must admit I'm looking at the iKON iq brand because it's hypoallergenic and if you spend so much you get their lamp too!! xxx
...another thought after reading another thread...what brands are you using, make sure it's proper stuff with non of that MMA etc!! If you have any of that, I'd switch system asap! (I'm sure you're not using it but just wanted to make sure!) xxx