@penn19 I don't know the reason you have been advised against a second shot, but I thought I would share my sister's story in case it might help you. She had an absolutely horrendous reaction to the first Pfizer shot, about 11 hours after receiving it. Consequently, no doctor would approve her getting a second one or substituting with Moderna, as they are so similar.
So after consulting with three different doctors, one being an allergist, they all agreed that she should get the J & J which she did, about 4-5 weeks after the Pfizer. She did not have a reaction to it but as she is 54, they told her to watch for signs of a clot for the next two weeks. Thankfully, she finished the two weeks now and has not had a problem, although she is still dealing with some of the problems caused by the Pfizer.
If you want to be fully vaccinated, and you had a similar kind of issue reacting with one type, maybe you can consult with some doctors to get their opinions about changing your vaccine. Just another idea.
So after consulting with three different doctors, one being an allergist, they all agreed that she should get the J & J which she did, about 4-5 weeks after the Pfizer. She did not have a reaction to it but as she is 54, they told her to watch for signs of a clot for the next two weeks. Thankfully, she finished the two weeks now and has not had a problem, although she is still dealing with some of the problems caused by the Pfizer.
If you want to be fully vaccinated, and you had a similar kind of issue reacting with one type, maybe you can consult with some doctors to get their opinions about changing your vaccine. Just another idea.