Sleep regression at 3 months?

My LO is officially going to be 3 months in a few days and his sleep as gone down the toilet.

Before this is sleep wasn’t perfect but it was improving, the first stretch was 5 to 6 hours and second was 2 to 3 hours, then followed by another 1 to 2 hour stretch so he was waking about 2 time a night.

But now his first stretch is 3 hours and then he’s up every hour, it’s been going on for the last few nights.

He was ill with a cold 3 weeks ago so I thought it was that but his congestion has completely cleared up and the cough disappeared but even then he was sleeping at least 3 to 4 hour stretches.

I follow his wake windows using the huckleberry app but I also follow his sleepy cues. He goes to bed between 7pm to 8pm and I also follow the same bedtime routine. I did adjust his last wake window from 2h to 1.5h to see if that made a difference and it didn’t.

He has between 4 to 5 naps per day and his naps are about 3.5 to 4.5 per day. Wake windows are 1/1/1.5/1.5/2

Does anyone have advise or have a been or in a similar situation.