I got a new bed and I can't tell if my body is responding positively or negatively.

I got a new bed. The first time in my life I have an actual brand new bed. Normally I need at least 7.5 hours to have a good rest and even then I will want to stay asleep. With the new bed if I sleep for more than 6.5 hours I feel like crap. But if I wake up before that I feel fine. Am I just getting a better quality sleep? Like, is my body rested in less time because I am sleeping better? Or is it bad that I can't sleep for 7 hours without feeling horrible when I wake up. By horrible I mean I wake up foggy and my teeth hurt and I feel a weird pressure in my chest.