1 month old is a HEAVY sleeper. Is this normal?

My son is 3 1/2 weeks old and he is a super heavy sleeper sometimes and it scares the 💩 out of me.

Last night I went to check on him after we finished eating dinner. He had been asleep for maybe 2 1/2- 3 hours and he was out cold. When I picked him up he stirred a little bit and stretched but wouldn't open his eyes. I tried changing his diaper, undressing him, tickling his feet, talking to him, and wiping him down with a wet wipe. It took a good 20 or 30 minutes to get him to wake up. I ended up having to ask my mom for help to wake him up because I was slightly panicking at this point. He had done this one other time when he was about 2 weeks old.

He was born 9 lb 1 oz and gained back to his birth weight within the first week, his pediatricians not concerned about his weight gain and says that he's on the right track. I'm just a worry wort and he's my first little one. Is this normal?