Hi Ach
I think it's ok to be scared - just don't let it paralyse you.
You've done really well in your studies so far - there's no reason to think that that would continue so long as you put in the same effort and standard of work.
As for the feeling alone bit - I think you're still hanging on a little to that last relationship....
You won't be able to move on to a new one (at least not successfully) until you let that go.
Just my opinion but I think you've spent enough time thinking about your ex and that relationship
It's a new season and a fresh start Ach
D