Yes it will come back, situations are different, but it will come back. I felt like this not too long ago back when I was in school. This started a couple years ago and stress can be such a bummer. Especially with exams and tests it is difficult to concentrate, and easy to be distracted.
I was diagnosed with depression in highschool and spent the majority of my last years down in the dumps, I was also at the beginning of when I started to take the Church seriously. Things will get better with time.
Now, for me, I dropped the university after mt first semester, I wouldnt recommend of course. But whats helped me get through my tough times is a couple things.
Acknowledge Life is up and down, God is with you even when we feel like we cant do anything. One thing that can help is learning to focus for periods of time, studying in small bursts and not all at once. Even as simple as not overthinking can help.
I can assure you, once I stopped overthinking alot of my situations, it became alot easier to think clearly and sober. Pray, of course pray when you get overwhelmed and thank God for anything. Also ask him for peace and his wisdom to get through these dark moments.
Hopefully this helped a bit!