TGI, Rambam in fact says that if one exaggerates a certain characteristic one should go to the other extreme temporarily. In fact, Shidduchim and Zivugim advises new BTs to wait until they become comfortable in a derech.
Shopping, why can’t you eat their food? I think that you should have a conversation with a rav who can explain to you that there is only one Jewish people as well as the fact that b’diavad is also a b’diavad situation, the exceptions where people will become angry, etc.