Do Pregnancy Symptoms Decrease During The First Trimester?

Hi I did a home pregnancy test and the result turned out to be positive. I then again did the pregnancy test a couple of weeks after at the doctors and this time the second line was faint and I was told to do another one at home. I did after a few days later..and I got the same results as the second test. Also I have found that my pregnancy symptoms have slightly decreased such as feeling nauseous as I believe I was still in my first trimester. Is there a reason for me to be feeling concerned?