Should i take this medicines while pregnant?

im 8 wks pregnant and ive been going to a dr since before i got pregnant i was taking a supplement called immunostart and it works great and now hes recommending one thats called siga it has everything from the moringa olifeira ive researched online and its says that its the tree of life, its supposed to help you with your immune system and it helps against so many things, he says its totally safe during pregnancy since its natural im just worried about the flu/swine i dont want to get the shot never have gotten before so im really scared this is my second baby whats your opinion thank you