Woke up with my stomach hurting this morning

Hiii!! I woke up with my stomach hurting! I'm on birth control! The pill! I finished all 21 of the pink pills but I started the white pills yesterday I took my second one this morning ! However I woke up with my stomach hurting and a little bloated! The bloating went down! What does this mean? For people who have been on the pill and experienced this before? Does it mean my period is on it's way? eve said I was supposed to start yesterday but it hasn't showed up since . Please help me understand this! Thanks 💕