What is wrong with me and how do I change it? am i too obsessed with my best friend? Please help me thanks?

okay so i have a BIG problem and its kind of overtaking my life and it has been for quite a while.....so my best friend and I are both 19 year old girls and we are both straight completely.. so anyways I think I am too obssessed with her or too attached to her I dont even know what to call it because I dont kno what it is but its like she is on my mind 24/7 i mean we text each other all day long everyday but like she could go a few hours without texting me and doing her own thing but I usually get anxious if i dont get a reply from her within 10 mins and i keep checking my phone to see if she texted.me.. like if she was a guy or I was a guy it would be easy to conclude that I'm obssesed or in love but this is my best friend and shes a girl and I am not in love with her I love her ofcourse but not in that way...but anyways so its like I get so upset when she cant hang out I even cry.. like yesterday she was home alone and i asked her to come over and she just wanted to spend her time doing her own things reading n stuff n so she didnt feel like leaving the house n driving to my house she said it was a pain and I got so upset that my best friend thinks its a pain to come see me ..like u see i kind of just take it the wrong way i guess and take it too personally and then i cry..and then sometimes i ask her if she can come over but she can't and later on i ask her what shes doin and shes with some other friends and then i start crying thinking she doesnt want to hang out with me.. I mean i am very sensitive and i do cry over very little things but i dont understand why I cry if my best friend cant hang out with me for a few days like i know i'll see her soon its just i always want to hang out with her .. and i guess its hard bc she is independent and she does things only if she wants to so if i asked her to do something she would do it only if she wanted to but me if she asked me to do something i would do it even if it hurt me or even if I hated it I would do it just for her........ so can someone please help me and tell me what I can do about this I dont want to be so attached to her i love our friendship its truly great we have amazing times together but i need to stop with the crying and getting upset over little things like if she doesn't want to talk on the phone or if she can't video chat or come over etc..