Sleep regression?

My son will be 4 months in 2 weeks and the last few days he has been super fussy. He sleeps 30 minutes and is awake for 3-4 hours or he sleeps 4 hours straight during the day. At night he was sleeping 8 hours but now he wake up every 2-3 hours, he nurses for a few minutes then goes back to sleep. Nighttime isn't that bad for fussing, he has a harder time getting back to sleep but overall he's okay. However during the day he fusses and will, what I call "angry cry" because he's so tired but refuses to nap. I'm pretty sure this is just sleep regression because he doesn't have a fever, he's eating like normal and does have some happy moments. I just want to know if this is normal? Being a first time mom is the most amazing but scariest thing all at once 😣 I just want to be the best for my little man but right now I feel like I'm failing