J.S.
I have two daughters - a 3 year old and a 1 year old and the pregnancies were completely different. With my first I was sore all the time and I got sick every day from 6pm - 8pm on the dot, which at the time I hated but looking back the predictability of it was pretty convenient. That continued until about 14-15 weeks and the symptoms gradually disappeared.
With my second girl I would get sick on and off throughout the day and night. Nothing to predict it and no way to tell how long it would last. Sometimes I would be absolutely fine for 3 or 4 days before it would hit me again. The girls would be sore on and off as well. I had a previous miscarriage as well, so the coming and going of symptoms with my second was an emotional rollercoaster for me. But everything was fine and she is now 1 year old. Every pregnancy is different and your body is going to react differently to each one.
Congratulations on the pregnancy! Talk to your Dr, s/he should be able to help ease some of your worries. Also, have you heard the heartbeat yet? I think the chances of miscarriage drop significantly once the heartbeat is heard.