Tahajjud gave me exactly what I wanted but my heart is not at peace.

I prayed and prayed and cried and cried for this. Yesterday, I got it. I got admitted into my dream university inspite of having very poor test scores. Ideally, I should be very happy but now I constantly feel restless. I feel lonely and scared. I feel like I am too dumb to be at this place. I feel like I'm gonna fail and end up nowhere. I feel like the world is too big and I am too small. I also feel like I am straying away from prayers and Allah. I thanked God in my prayers for granting me my wish and to help me calm down. I am having second thoughts on the thing that I was crying for literally 3 days ago. What do I do? I cant even talk to someone about this cuz I will be called ungrateful.