Nap tantrum/terror?

My 2 1/2 year-old son, ever since being home from daycare due to the pandemic, throws many tantrums after his nap. Some are better than others. I figured it was a phase. He hadn’t had a bad one in quite some time. Occasionally, it will last up to 45 minutes of him just throwing himself on the floor unable to understand why he is so upset. Earlier, there was a new type of tantrum that scared the crap out of me. He woke up after 45 minutes into his nap crying for me, and then proceeded to keep his eyes closed and thrash himself around for another 45 minutes. At times, I had to restrain him so that he wouldn’t throw himself off the bed. It was like I could not snap him out of it and he wouldn’t open his eyes. He seemed scared and was shaking. I finally was able to get him to open his eyes and now he is totally fine. Does anyone have any insight or advice? This was not your typical tantrum. This scared me so badly.