Was this even sexual assault ? Was it my fault , because I led him on ?

Okay so I'm sorry if this turns out to be a long story , but I am so confused and dying to know the true answer . So , to start off I was friends with this girl who had a little brother , but is still older than me . He texted me anonymously on this app asking for nudes , but I didn't know who he was until he eventually texted me . I didn't give in to nudes , of course , because I've never done that , but me and him still talked ever since and I didn't ever consider him liking me . Anyways , he told me I was pretty and stuff like that . And I didn't realize he thought that about me . He then started talking about wanting to have sex with me and I didn't think it would go too far , but I did lead him on and I feel bad for that , because at times I did sound like I wanted to , but in reality I did not . I don't know what I was thinking . Eventually , he wanted to go with me across the street from school one day and do it , except not everything , because I was on my period . For some reason , I did go with him even though I didn't wanna go with him so I had no idea what I was going for . I wasn't ditching class or anything , but I did go during lunch time . While walking with him across the street , he kept asking me if I was okay , because I was being quiet . I didn't think anything bad was going to happen , but we eventually got there and he started touching my sides , my boobs , and then he just kissed me out of nowhere . I did kiss him back . But I started to freak out . And he said shhh it's okay and then kissed me again . I then heard a zipper and he had both of my hands , because he was holding them. and all of a sudden , he put my hand on his thing . He started moving my hand with his . I started freaking out inside , I began to feel paralyzed ( frozen) and emotionally numb . I pulled away and he put it right there again and continued . I think eventually he did let go , but I acted so innocent with him . I was to trying to get out of it anyway possible . He wanted me to go down on him and I refused . I would try to stand up , he was holding my head and he would pull me back down by pulling my shirt down . I told him I wasn't ready and it didn't feel right . I tried to get out of it , by asking if we could do it tomorrow ( obviously the next day ) and he said " No , because I know tomorrow you won't come . I eventually was able to leave , because the bell rung to go to class and I felt so horrible afterwards . I was still numb and after school he texted me , telling me I freaked out . This has been bothering me ever since . I know I probably sound young , but I'm not that young . I'm just trying to make this sound less bad as possible . I've been having constant dreams about him ever since and it's almost like he's haunting me . What do you guys think ? Thank you for reading .