Strange /feeling/

I am now 30 weeks pregnant, so excited and happy for it. But for the last few days I've had this really strange "just know it" feeling that my boy isn't going to stay inside me much longer. I'm a first time mom and maybe I'm just not used to the physical feelings but I just honestly feel this baby is going to try if not succeed in coming early. I tried telling my mom about it but she brushed it off. It's honestly a mix of physical and mental things that have me feeling this way. What are your thoughts? Am I just crazy or could there really be a reason behind my feeling?