Please help... i am nervous....

Amanda • 24 yrs old. Mommy to a beautiful 3 year old he is my pride and joy. And now we are expecting our 2nd on july 25!
I am about 4 or 5 weeks I have been to the doc but don't have an ultrasound until Dec 8th. I was having mild symptoms the last two weeks feeling hungry all the time sore chest and slight nauseousness and now those are gone and I don't even feel pregnant. Anyone know if this is normal this is my second baby but I didn't experience this w my son please help