The urgent need to eat in first trimester

I wanted to see if others have experienced this. During my first trimester, I would become very weak and shaky and need to eat immediately or I felt like I was going to pass out. Since I entered my second trimester, it's gone completely away. My glucose levels were fine, so I'm wondering if it's just a normal part of pregnancy. I won't be seeing my doctor for a few more weeks, but will ask when I see her again. Have any of you experienced this as well?