My friends keep hanging out without me?

So i have a group of friends. At least that what i think i am to them, and they always go out without me numerous times! And they only invite me rarely , they even have a group on a social media plateform that im not even on, and i just dont get it? I've been there with them since the beggining even before some of them became friends to each other, i've been very close to each one of them for years, and at school i try as much as i can to hang out with them because i enjoy my time with them and i know they love me. But i just dont get it, like today i went out with them for the first time in forever and when i left i looked at my social media and found they took a picture after i freaking left and posted it! Like that just hit the last straw and im hurt beyond words like i just think that's god sending me the last message like he's telling me wake up!
My friends keep hanging out without me?
Post Opinion