Why does your Dr. feel that following a vegan diet is going to give you weight loss success?
You're right ... switching to a vegan diet can be overwhelming!!! There is a huge education curve to it. In order to eat vegan, in a healthy way, nutrition can be a huge issue and concern.
Please note, I am not saying, do not go vegan, but to do it in an informed way, knowing why you are doing it, and understanding the basis of it.
I have several friends that are vegetarian or vegan, and several have said that eating "healthy" is actually quite difficult to ensure balanced nutrition is met. Also, that following either can make it difficult to maintain their weight, let alone lose weight. Thus why I asked the reasons your Dr. is urging you in this direction.
As already suggested, talk to knowledgeable people before making the decision. Working with a Registered Dietitian can help you to not only make the decision, but to also put together your meal plans, keeping nutrition in mind.