I always wanted a Guinea Pig as a pet. One time I cared for a friend's rabbit while she was vacationing. I had a mild allergic reaction to it. So would I be allergic to Guinea Pig? From what I found online, they shed seasonally. And also, is there a relatively non-shedding Guinea Pig?
If the rabbit also causes an allergy, you might consider a smaller pet. A guinea pig is a fairly safe bet for most people with allergies. If you find that a regular guinea pig causes some allergy symptoms, you might opt for a hairless guinea pig. Hairless guinea pigs actually do have hair that some people call peach fuzz. The lack of fur makes hairless guinea pigs very safe for people with allergies.
And, this Quora answer states:
Not necessarily. They are distinct animal danders. On the other hand, it’s not uncommon for an allergic individual to be allergic to several “furry” or “hairy” animals.
It’s relatively simple to be allergy tested by skin or blood to determine if you are allergic.
So just get tested for allergies. Since they are different species, you wouldn't specifically be allergic to a guinea pig just because you were allergic to a rabbit. You should also double-check that you're allergic to the rabbit, not the rabbit's hay, food, home, etc. If allergic to those, try your best to buy alternatives for your guinea pig, if this is too difficult or there are no other alternatives, the guinea pig may not be best for you. I've heard goldish are pleasant.