Are my glasses making me sick?

For the past two years, I've been wearing only contacts and purchased a new pair of glasses to give my eyes a rest a night. I received them today and when I put them on things looked a little awkward and disorienting at first. After a few hours, nothing had changed with my vision and I started getting a little queasy and developed a slight headache. I put my contacts back in about two hours ago and the headache and nauseous feeling is still lingering... Are my glasses making me sick? Are they too strong? Or is this just normal and something I'll have to adjust to gradually?