Is this the 4 month sleep regression?

My son is 4 months old, he was doing really well with naps and sleeping at night. He would sleep in his crib for naps & at night he would easily go back into the crib after nursing and having 6 hour stretches.

Now he will occasionally nap in the crib but mostly will only fall asleep if I'm holding him or nursing him. At night he will sleep for the first stretch (2-3 hours) in the crib but after that he's up every 1-2 hours and doesn't want to be in the crib. He'll only sleep in my arms or if I bring him in the bed and I have to nurse him back to sleep. I don't want to co-sleep but right now it's the only way I can sleep.

He's teething as well right now so I don't know if some of this is because of that.

Is this the 4 month sleep regression?

Any recommendations to help get through this?

I use the huckleberry app and follow the sleep recommendations but nothing seems to be helping.

I have alot of anxiety that I'm doing something wrong and that I'm making terrible sleep habits.