For experienced pregnant people

Crystal • Married for 5 months together for 7 years, pregnant with baby 1. Scared to death!
My sister had her "period" for 3 months when she was pregnant and never received a positive test until she was 10 weeks. I'm wondering if anyone else has experienced this or similar?   
​According to when I got a positive test I should only be a little over 4 weeks. I havnt missed my period until now...but my period was shorter and very clotty.  Last month I experienced nausea and achy breasts and my breasts grew and are still larger! I've also gained 16lbs in a very short amount of time. Now I have none of that going on, but I do have a positive test. Has anyone else experienced anything similar? Did you end up being way further along then the test and your "period" told you?