I just looked around on the internet to see what research says about the issue. Multiple studies have been performed on whether or not there is a risk of taking Amoxicillin while pregnant. There is no absolute answer but research does not appear to show any direct risks to you or your baby. They do advise to use caution if you are currently nursing because it is released in breast milk and there is the possibility that it could cause the baby to become sensitive to the drug later in life.
The reason you were given amoxicillin specifically is probably because it has been around for many, many years and thousands, if not millions of women have already been in your shoes without experiencing a problem. The doctor probably avoided newer antibiotics because there is less known about them.
Putting research aside, doctors and patients must look at the risk / bennefit with every course of treatment. The risk of you becoming sicker if untreated is high. The risk to your baby appears to be extrememly low. The benefit of the treatment is that your health will return to normal. Remember that if you do not take care of yourself right now, it will be harder for you to develop the miracle of life inside you.
Good luck to you
