Dentist while pregnant?

So I've needed to get a few fillings and a root canal for a while now but help off until i hit my second trimester.  My dentists insisted I could get work done my first trimester but along with being sick, I wasn't comfortable with it. Not only that, but when I told them I was possibly pregnant the dental assistant asked me if it was planned (I of course got offended) and then proceeded to tell me if i wasn't I shouldn't try because kids are terrible.. And went on about how she has a son and he just had a baby which she wasn't happy about.. So I don't exactly trust her for shit honestly. But I can't switch dentists because I just did and my plan only lets me switch once a year. My dentist is nice however, just her assistant really pissed me off. They told me I could get work done under novocaine and that it's completely safe. Anyways I'm now 15w4d and I wouldn't get an appointment for another few weeks anyways. Is this safe? Has anyone gotten fillings or any dental work done while pregnant? Were you on novacane ?