Anyone notice their toddler being very clingy since being pregnant?

Ever since I've been pregnant, my son has been clinging onto me. He's currently 18 months (almost 19) and I'm 5 months along. He sleeps in our bed so he always wants to be on my arm or climbs on top of me. It wasn't a problem before but now that my belly is getting bigger I'm very uncomfortable and I need to reposition myself constantly. He also cries if I move away or take him off of me. Anyone relate??? Is this a sign of him being jealous towards his sibling already? How do I deal with his behavior? We've tried so much to teach him not to do it but he's very stubborn about it 😭 I'm worried he may hurt my belly one day