is it normal when friends don’t reply to you sometimes ?

i haven’t really had many friends and im kind of slow so im not really used to these things. i sent my friend a couple tiktok’s but he didn’t view or respond to a single one. the thing is he sends me a bunch of tiktok’s and i watch all of them and respond because i feel bad if i dont. he never really responds to the videos i send him unless i stop sending videos or responding to his videos. another friend of mine will randomly just not respond to my messages. we could be mid conversation and he just randomly doesn’t respond for 30 minutes to an hour or longer. like earlier today we were in the middle of talking and he just stopped responding to my messages but sent messages to our group chat. after a couple hours he responded to the message. he does this a lot and i feel like im being clingy. is this normal and am i just overthinking?