Help: Baby waking every 30-60min at night!

I need help: My 5.5 month old baby is waking consistently each night every 30-60min. We are lucky if we get in a 2h stretch. He cries every time he wakes. Could this be a scheduling issue or what is going on? We are on a 7am-7pm schedule with first nap at 9am and WWs 2/2.25/2.25/2.5. However, since introducing these WWs I struggle with overtiredness and sometimes let him take a naps after a 1.5h WW. So the schedule inconsistent. Due to the very frequent night wakings, he is very fuzzy during the day - seems we are stuck in a vicious circle. How do I get out??

Baby falls asleep independently in his crib at bedtime with a paci after sleep training at around 3.5 months. At night, he only falls asleep again after nursing or when holding him very close / co-sleeping. We are so so tired, this has been going on for about 6-8 weeks!! What are your thoughts? Thank you!