Nausea signal means your blood sugar is low. At least... that's what it means for me. First time it happened, I was out all day playing paintball. Around 4 we stopped to go home and I was feeling nauseous as hell, went to a payphone to call my mom and have her come get me, throwing up mid-phone call. She thought I was just faking and told me to walk. But I felt so tired. I sat down and fell asleep for a little bit. Got up and started going home. Kept throwing up, and passing out. My best friend ran into me while skateboarding over to my house and I told him how I felt so he mashed off to my house to get my mom to take me seriously, but before they got back I guess someone called 911 and an ambulance showed up and checked me out. Had a blood sugar level of like 20 or something ridiculous on the meter and they gave me some juice and told me to get home and eat. Now any time I feel hunger pangs at all, I eat something.