I myself would put the dog inthe crate in the evening before he goes into this mode. It sounds like a normal FRAP movement when a pup gets all excited and runs around, but they normally don't get up from sleeping and run around rather they are already playing and they get a build up of energy. This is a weird behavior. I don't know how to fix it but I would start during the day with laying him on his side next to you and holding him on his side until he stops wiggling while you talk gently to him. After a minute of him being calm let him up and praise him. This will help him trust you while teaching him that you are in control, especialy when it comes to deciding when the play sessions need to end. I still do this when my Autumn gets too excited and it calms her down good, of course she not as huge a dog. Have you looked at obedience classes yet. Its never too soon to start a long as you keep within the limits of a 3 month old pup. Short, fun training sessions.
I'd do a few things for the fear of going ouside. First I'd tie a small bell to the door within his reach. Each time you let him out help him to nudge the bell then praise him when it makes a sound. Evenually he will learn to ring the bell when he wants out and being by the door won't be a scary thing. Make outside time as fun as possible and if he has learned the bell you can get one for outside or even teach him to hit a low doorbell, it will save you from door scratches or barking. If being outside is getting stressful or him is reassured that he can hit the bell and go in.