Sleep help!

DS is 7 months old. Up until about 5 days ago we haven't had any sleep issues. We have a strict bedtime routine, which usually entails DS falling asleep during or soon after his last bottle, being put in his crib, and sleeping 10 or 11 hours a night. On Saturday, he started throwing HORRIBLE fits during bed and nap time. He kicks, pushes, arches his back, and screams. He's dead tired because he rubs his eyes and face all over whoever is holding him. He has two teeth that are SO close to coming through, but he is super happy the rest of the day. I don't think he's sick because he has no temp and is happy the rest of the day. We are out of town with my parents, so I knew things would be shaken up a bit, but this started on Saturday when they got to our house before we even left for vacation. The only thing I can think of is that he's used to it just being me and him. DH is deployed and I'm a SAHM, so maybe he's not used to having other adults around?It's totally unexpected and literally out of the blue. I'm at a loss for what to do and just want to go back to our happy, calm bedtime. The only thing that has worked is if my dad takes him outside and walks around until he falls asleep. Any advice or suggestions?