Oh, I am SO sorry about this.
I have OAS, too. My (pollen and cat) allergies started at the end of high school, then in college I discovered my apple allergy. It was actually a pretty funny story - I was talking to a friend and mentioned that everytime I ate apples my mouth got super itchy, my throat got scratchy, and my lips swelled up. She looked at me like I was an idiot (which I was) and said, "Duh! Think you're ALLERGIC?"
Honestly, it had never occurred to me.
I'm currently only reactive to apples and cherries, but I think nectarines are starting to be bothersome. I live in fear of the day all my fruits and veggies are taken away. How awful.
Did your allergist suggest allergy shots? I've heard that that may be beneficial for some people. It sounds like you're allergic to alder pollen, like me.
I hope dealing with this gets easier!