When to worry?

Samantha • I am me.
How do I know when cramps mean something's wrong? At the beginning of my pregnancy they told me the cramps were normal because your muscles were stretching but now I am in my second trimester and today I started feeling some sharp pain in my lower abdomen and I haven't had any cramps for a long while since the first 6 weeks of my pregnancy and now I'm just wondering when I should worry and go to the doctor. Any advice would be great!