Hi Doctor, I'm 6 Weeks Pregnant Now, I Keep Having

hi Doctor, I'm 6 weeks pregnant now, I keep having this fullness feeling in my stomach, distention like, where my abdomen looks so big as If I'm 6 months pregnant, painful and discomfort, with nausea all the time. don't know what is the reason behind this, knowing that I had the same symptoms in my last pregnancy before miscarriage!!!