What’s Going On?

Okay So I Got On Depo Like A Little Over A Week Ago Right? So I Been Having Unprotected Sex Of Course ... & Today I Was Supposed To Start My Period & Instead I Woke Up To Some Light Dark Dark Brown Spotting & Light Cramping That Comes And Goes 😱 Than Yesterday All Day I Was Very Very Nauseated 🤢And Was Having Bad Bad Headaches 😭 I’m 18 And I Been Getting Depo Since I Was 12 And I Never Experienced Any Of This Could Somebody Please Tell Me What’s Going On ? Should I Go To The Doctor ? Btw The Spotting Stopped After I Saw It Earlier This Morning