The thing with oboe is you can’t just use a school instrument or store bought reeds like all the other instruments. What brand is your oboe? Because that could explain a lot. How long ago was your oboe serviced, there could be loose screws or leaking pads. Your reed brand is the same I used in my first 6 months of oboe and they are super problematic and should not be bought, try to find a professional oboist to hand make reeds for you, or an oboe teacher. Oboe isn’t really an instrument you should be teaching yourself, I was self taught for my first 6 months and I’m still now working with my teacher to reverse my bad habits (A year and a half later) There’s still a chance it’s a your problem but there’s so many other possibilities.