how do i stop being so desperate for his attention??

i (22f) met a guy (23m) from a dating app around three weeks ago and have (unfortunately) since then developed a serious crush on him. we were both due to graduate this month so it was already obvious we wouldn't be living close to one another after meeting, but i didn't think i'd end up liking him this much. it's torture. i keep thinking about our date and i get butterflies (he was my first kiss which may play into why i got so infatuated so fast).
however, we haven't talked much since the date - life got busy with graduation and moving for the both of us, and it seems he took it a lot more casually than i did. i'm really struggling with that. i always want to find a way to talk to him and get him to notice me, like posting instagram stories or liking his social media posts. it does work sometimes and i get that instant gratification from it but then we go back to not messaging and the cycle starts again. i hate it sooo much! i know i need to get over it - seeing him following loads of other girls on social media and updating his dating profile, but then calling me pet names like 'cutie' or saying he wishes he could snuggle with me in dms is messing with my head. while i personally would be open to taking it further (i'm in a transient point of my life where i'm open to living anywhere eventually if i have the means) or even just travelling to meet again once more to further explore the connection, he definitely seems to be in the more casual dating scene than me. i'm worried if i keep it up i'm just gonna be considered as an option by him because i'm always so quick to respond and flirty with him when we do talk...
how do i get myself to stop thinking about him all the time?? how do i stop myself from stooping to such levels just to get a message from him?? and not be so jealous that his social media and dating profiles prove he's like this with other girls?? it's driving me crazy! i've never been like this about anyone