I’ve read research showing that the components in grapefruit (extract as well) can interfere with certain medications, but it doesn’t sound like you were on medications for your asthma, correct? I also know that GSE can boost the immune system which also shouldn’t interfere with your asthma. If you wish to test it, just stop taking the GSE altogether and see what happens.
Mold is a microscopic fungus which can trigger an asthma attack (as you probably know); have you had enough rain to produce more mold than normally would occur after a period of rain?
Have you thoroughly checked your house for mold in the last few weeks following so much rain?
The fact that your hay fever is worse as well may be an environmental clue.