Confused 😕

I started my period 4/11 and ended 4/17 and have pretty much bded since the 17th. Acording to glow today is my first fertile day but this morning around 5:30 am i experienced some sharp pains on my left side (dull sharp throbbing type of pains) lasted for about 10 minutes and that was it. I wasn't gassy and there were no other pains. I usually have a 31 day cycle but had my nexplanon removed 3/5 and didn't have a period for that month so I'm not sure if they returned to normal or not. What do you ladies think it could have been?