Second fear period? Help please!

I have an 8 1/2 month old lab/McNab/Border collie/Malinois mix. He is an amazing pup, great temperament and sweet as can be. Well he was crate trained and grew out of it, not in size, but in that he was just fine chilling in the living room while I am gone and napping on the couch and the floor, so we got rid of it. He did fine without it. Well about a week and a half ago he got spooked by the wind outside and ever since then he has not been the same puppy at home alone. He tries to nap when i leave, but he will constantly perk his head up and start scanning the environment, as if listening to every noise. And he doesn't have separation anxiety per se, like he is fine with me leaving, but if he gets spooked or if too much time passes he escalates to where he is whining and panting and pacing and trying to bust down the baby gate. I try to come home before it gets to that point, and have been like a prisoner in my own home trying to get through this. He seems maybe slightly more jumpy in general, but nothing too crazy. He has always been a cautious and sensitive guy, but not anxious or fearful and he is extremely resilient. Even now if he panics at home, as soon as I get there he is able to flip a switch and start playing and then crash out. It is so weird because it just came out of the blue, and is just not like him. I tried to give him some Pet Naturals calming chews, and i was hesitant to try because I don't want to mess with his developing brain, but I needed to go out to church. Well he slept hard for about 45 minutes, then he was awake and alert, but not panicked for another 20 minutes, then he started pacing and whining and trying to break the gate down, at which point I was almost home. When I got home he was excited to see me, then wanted to play then fell asleep. Is this a second fear period? And will it go away? I love my puppy with all of my heart, but I live alone and don't have anyone to help me. I hired a dog sitter on Sunday morning so I could go to church, and it was 60 bucks..I will hire him again this Sunday, but it isn't sustainable long term. I do not want to rehome my puppy, it breaks my heart just thinking about it. I suppose if it continues I can ask the vet for some anxiety meds, but I really don't want to do that. My puppy has the sweetest personality and I don't want to dampen that with medication. Please any advice or encouragement would be appreciated!