Did you feel any negative affects from it..? If you didn't feel anything then you & baby should be OK. There are people who have a higher susceptibility to toxins, especially mercury, and they would be experiencing some negative affects. It is believed this can be genetic and I believe that my family has this susceptibility causing ALS, autism, aspergers, and bipolar disorder in my extended family. I have read that about 10% of people don't handle toxins properly. For those that don't even a tiny amount can be toxic. They get sick after vaccines for example. For those that do handle toxins properly they can be perfectly OK.
You would know if you were one of these people that could not handle the toxin load. I once saw a forum post by a woman who had the CFL break happen to her. It took her 1 year to be in her home without a mask on afterwards and she couldn't even approach her street in the weeks after it happened without feeling like she was dying.. her husband had to completely gut the house and new paint, etc. She says that her hand that touched the lightbulb turned green afterward and nobody believed her.. Now she is affected just walking down the street by fumes from the vehicles. I don't say this to scare you but to show you that if someone was going to be affected by it you would know it. If you sat there all day next to it and didn't even feel anything then you and your baby should be just fine. Me on the other hand - given my family history I would be super nervous if this happened to me.
But if you are still worried selenium & zinc are supposed to safely help protect you and the fetus from mercury. Selenium especially binds to the mercury making it less toxic. So I would start taking extra doses of those 2 things but be careful with the selenium.
If you start googling about mercury and toxicity you will likely hear about chelation DO NOT DO THIS when pregnant because it will dump the toxins out of your body.. but into your baby. Only selenium & zinc can help while pregnant as can a healthy diet.
But like I said - if you sat there all day and didn't feel anything - woozy or headache, etc. - then you likely have very strong genetics and will be fine.
PS - Just noticed that this happened a while back. Even more likely baby is fine. People that don't handle mercury well often experience a miscarriage directly after high mercury exposure such as the swine flu shot or dental work. Since this happened a while back and the pregnancy is still progressing normally, this is another good sign that the vapor did not affect you 2 - at least not enough to cause any major harm.