M.M.
First off relax. Do not release extra endorphins into your body by being a nervous getty.... If everything formed right from conception then the pregnancy will progress. What you are describing actually is a textbook pregnancy. Your hormones shift and change when you hit 12 weeks and it use to be referenced as the "magic" time... Women would wake up and over-night feel like a new woman. So, not a sign of miscarriage but of hormone switches. This is the reason we tell women that once they hit the 12 week milestone to celebrate. So instead of worrying; 'freakin A'; celebrate. It will not last long. The feelings of discomfort (just in other ways as your body grows) will be here before you know it. Congratulations.