You have been really unlucky with your previous dogs, but you must put that to the back of your mind.
I really think you need relax and enjoy your new puppy. Don't stress or over analyse things. Don't panic and assume that the same things will happen again.
Remember that all our dogs have little quirks which don't make them perfect! Rules, boundaries etc are really important but don't live your life by them. Don't confuse yourself by reading every dog training manual that was ever written, just decide what is important to you. I want happy, friendly but not over friendly, biddable, well behaved, fun and loving dogs. However, both my dogs have sensitive natures, can growl/bark when they feel uncomfortable about something, can be unsettled easily and want to be with be us most of the time! But I don't worry about these things, it's just the way they are. If I was to worry about every little thing I wouldn't be able to enjoy them and bond with them.