I blocked all of my friends and I don’t understand if I did the right thing

Over the past year or two, I've had periods of strong stress (mostly because of school, I'm very demanding of myself academically). During those moments, I sometimes had thoughts about cutting off all my online friends, but I never actually did it- I would calm down and move on.

Things got worse after I got an average grade on an exam. It hit me really hard: I came home crying and thinking that I'm not capable of anything and won’t succeed in anything.

I texted my closest friend (let’s call him Luca) and told him that I felt really bad and might disappear for some time. A day later he texted me, I explained everything, he supported me, and I felt better.

After that things were more or less okay until I had to defend an important project I had been working on for half a year. Before that, I made a deal with myself: if I don't get the best grade, I will block all my friends so I can fully focus on studying.

In the end, I didn't get the best grade, while almost all of my classmates got it. I sent a short message to all my friends saying I hope they’re doing well, then I blocked them and deleted our chats. The same day, some of them tried to contact me from other accounts, but I blocked those too. The only person I responded to was Luca. He told me that no matter what problems I have, he will always support me, and he asked me to explain everything. I couldn’t, and he said he doesn’t want to pressure me and that he will wait for me.

But the weirdest part is: I didn’t feel bad back then. I didn't feel regret or miss them. I just felt neutral. No crying, no strong emotions like before. I didn't understand why, and I still don't fully understand if this is normal.

At some point I even started thinking that I became selfish or narcissistic, because I felt nothing towards people who are actually close to me.

A few days have passed, and today I was watching a series and suddenly caught myself thinking that I wanted to share it with Luca. So I guess the attachment didnct actually disappear.

The problem is that now I feel very uncomfortable texting him. I'm afraid to explain everything, especially because I didn't miss them during this time. And I don't want to lie.

What should I do in this situation? And more specifically: what could cause this kind of emotional detachment, and is it normal?