Toddler kind of off

Does anyone else have a toddler that isn’t their usual self lately?

My 20 month old son used to go to daycare and used to be with my MIL and his cousins. He was a very happy outgoing baby.

Now lately, he seems very sad and distant. He lounges on the couch a lot and doesn’t really want to play with me. I also had a baby in November so he’s been home since then.

Tbh I am suspicious he could be autistic, but I am hoping that’s not the case and he’s just not himself because of the lack of social interaction