How do i get over her completely?

Heres my story: In 8th grade I fell for this girl, let's call her Sam, I have no idea why, but I just did. I didn't even hang out with her often

Anyhow I asked her out, got rejected... often. As time goes on I still like her, of course I cried/mourned about it, grieved about it etc. I cut her out of my life practically (I never talked to her). Yet I kept thinking about her every now and again, I asked out a few girls, but nothing really came out of it. I went to something like a military boot camp (encampment for civil air patrol) and through the big chunk of the time... I THOUGHT OF HER

I'm a senior in HS at that point and after I got out of encampment, I knew that there was no way anything could ever happen between us. I call her up and ask to talk to her so that I could eventually get over her. I talk to her and basically at the end of it all I told her that I wouldn't bother her anymore/try to make contact and I got closure.

I'm 20 now god dang it, it's been several years since I've talked to her, yet I still think about her. The other day family said hey you have to drink with us... I'm like K... after that I think i got slightly buzzed? I started contemplating on texting Sam and asking how she's been doing and all that good stuff(I memorized her number by heart and have no idea ho to forget it). I text my friend instead asking her to help me try to avoid that... she just tells me yo you gotta let go...

I'm laying down on my laptop thinking about sam still. The biggest issue is that it interferes with my schoolwork, I'll randomly start thinking about her in class or studying. Obviously I've tried letting her go, I went to ask for closure and I got it, I've cut her out of my life, I've grieved/mourned about it, I asked out other girls, tried to keep myself busy either with college,extracurricular(ROTC,Parkour,Cybersecurity,programming), or family. I'm a bit busy to actively look for a girl, not to mention seeking professional help, I want to do that after I get a BS or someone that really piques my interest come up. I'm not sure what to do at this point. I'm just sitting here realizing I liked this girl for 8 years, help please

TL ; DR I liked a girl a long time ago, but she pops into my head every now and again. Tried: not contacting her, being busy, grieving, asking other girls out, getting closure. WHAT DO NOW?!