If you'd cut communication or end a friendship with someone just because they don't return your so called 'feelings' it shows you were never a true friend to begin with. Perhaps you were only "friends" with her because you'd hoped it would get you into her pants.You can't have genuine romantic feelings for someone you've never dated, only a romantic interest (curiosity), infatuation, or desire for what you assume dating them would be like. At the end of the day you have no real idea what dating this person would be like or if you'd even be romantically compatible, you're only making assumptions based on your (non romantic) friendship. It's one thing to have a romantic interest and be curious to know if your friend has the same interest, but its another thing entirely to be confessing feelings or claiming to be in love with someone you've never dated. very cringe tbh
All in all, I'd say you need to stop being butthurt and treat your friend the way you'd want to be treated if lets say a different friend who you weren't romantically interested in asked you out. you would politely decline and continue being friends with them. However if you're obsessed with her to the point that you cant function as a normal friend, then its probably best for both your sakes that you cut contact and stop pretending to be friends. if you've been friends a long time and only just recently developed a romantic interest then i dont see why you shouldn't be able continue seeing her as just a friend- it shouldnt even affect anything. However like i said earlier, if she's just someone you havent been friends with for too long and/or you've always had this infatuation with her since the beginning (i.e were always hoping something would develop from your 'friendship) then just drop the pretence and move on.