Help!!!!

So i am 32 weeks pregnant and my dr is just now telling me that i have gestational diabetes. I think he is a liar and so does my husband but than I'm worried that he might be telling me the truth. I just don't understand why wait until now to tell me. I have been eating healthy and drinking lot of water but I really don't know about how to eat with gestational diabetes and all the reading I've done about it says that it last during pregnancy and could possibly last after that. I don't want to end up with it permanently if i in fact do have it. I just need help on what i can and cannot eat my dr said no rice, beans, potatoes, pastas, breads, tortillas, and sugars. But in my head I'm thinking at this point nothing else to eat except salads all day everyday.... i seriously need help.