Zero to hero to zero.. Is it really the lockdown?

I (20m) met the girl (19f) in December, after one month of her 2 years relationship. We were friends with benefits, but I caught feeling in January and she said "we have to turn things down before I make her loving me and becoming mess again". She gave me mixed signs, wanting me around and we even spent the Valentine's together. I kept things low to the point where she said: "Okay, give me time and we will be together probably." Two weeks later she called me and said: "we should go on a date and be a couple". Weird, but lovely. But lockdowns happened in March here. At the beginning everything went great – we flirted a lot, we played games and wondering about the world. She called me, I called her. She even says: "I like you too much and I am scared that you don't do the same way." I sent her a gift next day: my favourite book with a mail. And she freaked out. She didn't call me. Acted cold when I did. After 1 week she admitted she couldn't give herself in this internet relationship and wanted this lockdown end to see if we are still compliting each other. We argued and I asked her if it's really the lockdown that brings out these and not like her exes again check in or some other dudes. She said no and told me the only guy she initiated with in this year is me and if it's gone she wouldn't see anybody.

And here we are. I again keep things low, talk like we are friends. We watch Netflix together. She checks on me if I am busy. But no flirtings, less deep talk and I am concerned if it's really the lockdown… What should I do?