Sleep anxiety??

Dani
Is this a real thing?! Since the first day I brought my son home I would wake up 3-4 times a night freaking out and digging through the the covers to find him. The thing is, hes not in bed with us! My mind completely believes he is though and it's frightening. I never told my husband because it wasn't affecting him until about 2 months ago when I tried to push him over, which scared him thinking he had rolled over on the baby, baby was in his own room by this time. So when I got myself calmed down I had to explain to him what was going on. It's gotten better, so now it only happens once a night. Sometimes my husband has to talk me down and promise me that our son is safe in his crib. Friday night I had a bad night and did this 3 times and finally had to tell myself that our son was in his crib. It's really frustrating and feels like something is mentally wrong with me. He's 8 months old now so that's why I'm kind of worried about it.  Has anyone else experienced something like this? Is anyone else going through this? Is it a sign of PPD?