我暗恋你的英文表达为：I have a crush on you.
这个表达来源于英语中的一个习惯用语"to have a crush on someone"，意思是对某人产生好感、爱慕之情，但通常不会表现出来。
例句：
I've had a crush on her since we were kids. 我从小就暗恋她了。
I think John has a crush on you. 我觉得约翰暗恋你。
I can't bepeve I still have a crush on him after all these years. 我真的不敢相信我这么多年后还是暗恋他。