I just had a DNA test

I just got the most shocking news of my life I'm really distraught right now, and I dont have anyone to talk to at the moment, so I'm just going to vent on anon here if y'all don't mind...

For the past few years my Nana (my mom's mom) has been telling how she really thinks that my dad isn't really my dad and I should get a DNA test if I want to know the truth. I've been going through a very long depressive episode for the past two years, a lot of it caused by my very traumatic upbringing, with my father and stepmother. My therapist knew that what my Nana had said was still lingering in the back of my mind and suggested to put my mind at peace so I did. I took the DNA test and found out my father was in fact, not my father. However, I did share some of his DNA. He only has one brother y'all. SO BASICALLY I LIVED MY WHOLE LIFE THINKING MY UNCLE IS MY DAD AND MY DAD IS MY UNCLE. I feel so betrayed and denied of the happy life I was meant to live. I know its all the past now, but I can't help but wonder what things would have been like if I had known the truth, if they had known the truth. My mum definitely knew the truth, and she lied to me for 20 years I am so beyond mad, and hurt I don't know how to feel right now. My dad will always be my dad, and my uncle will always be my uncle. But things are different now. I secretly think my "uncle" knew, because out of all his other nieces and nephews he's always had a soft spot for me, always. He has favourites, but I've always been his absolute favourite and I could never fathom why, but now I know. He doesn't know I know, I don't know how to tell him. I don't know if this is meant to change things or not I'm just sooooo confused right now, where's Jeremy Kyle when I need him?!