We seem to have gone astray from your post. A G at the top of the staff after just two weeks back is good but not unusual. the muscles don't forget. What you lack is muscle tone. I would recomend to not push your range, don't be concered with it. It will come back when it's ready. the best thing you can do is chop time in an intelligent way. Short sessions of 15 to 20 minutes. stop BEFORE you are tired. A good exercise for you right now would be Study #1 from the Clarke Technical studies. Start on #8 and descend to #1. Rest between each one and play softly with a good tone. Take a full deep relaxed breath. Then #9 and ascend only as high as you fell comfortable. IMPORTANT: never strain or force extreme high or low notes. Then you should play mostly in the middle register. easy songs esp. ones with play along CDs. You may like a book called "40 Progressive Etudes for Trumpet" by Sigmund Herring. very melodic and with easy range. If you play a lot in the middle range, your range will come back naturally. Be prepare to take awhile say 3 to 6 months. The best advice I can give you right now is MAKE THE AIR TO THE WORK!. The main thing is to have fun and enjoy your comeback. Let us know how it goes.