Side effects of UVB lamp?

Hello everyone, I actually do not have psoriasis, but thought this place would be good to ask a question as probably many of you have used the UVB phototherapy. I recently purchased a small UVB lamp to use during wintertime to produce vitamin D. I used it a few times and yesterday, about 2 hours after using it I developed a headache, got really lightheaded, nauseaus and anxious. Woke up today still not feeling very well. So I wanted to ask, has any of you had side effects from the UVB lamp? I know what happened to me could be purely coincidental, so I thought asking about other people's experiences could be useful. Thanks in advance :)