I am 16 yo and I need some help. I can't find the words to describe my problems to a professional in a verbal conversation, so I'm gonna seek some advice here (also sorry if my English is bad, it's not my first language). 
I think I'm gonna start from the time when it all started. There is that girl in my school that I have been attracted to for 4 years. Around 3 years ago I have confessed to her, and got rejected. However, we were friendly towards each other, and are now actively communicating. The problems started in late May of this year. I have discovered that I am still heavily attracted, even attached to her. I have been subconsciously thinking about possible ways of getting her attention at night, and slowly developed insomnia. I was having insomnia this whole summer, sometimes once per week, sometimes 3 times in a row. I was overanalysing everything, especially if it had something to do with my relationship with this girl. 
Somewhere in July I became apathic. I stopped surfing the net, I didn't want to hang out with my friends, I stopped getting joy from things I liked, and was spending most of my time in bed, thinking. Apathy and insomnia ended in early September, but then new things started happening. I started having panic attacks, or whatever it was - I was feeling angry and anxious, sick and exhausted, I was punching walls and crying for almost an hour almost every day after school. I'm not sure if these are panic attacks or sensory overloads, but both of them are no good. 
We went to a therapist (or psychologist, I still haven't figured this out), and they sent me to a neurologist, who said these are probably hormones messing with me. He gave me some medications, and they didn't help at all. In fact, my hormones are mostly functioning normally. 
So after that, in the end of September, I started having suicidal thoughts. Not like I was planning on killing myself; I was having thoughts about death and the concept of it, about my purpose in this world and what makes me alive, what makes me myself. I was thinking about killing myself in the future (and I think the school psychologist heated me talking about this to my friend, so they might be sus of me now), but I didn't have actual plans. And then something happened: we had a very long interraction with this girl I was attracted to: we were walking together and I ended up in her house, going home late. This was truly euphoric, so I did everything again. And it almost worked. I started making progress, and was very happy about it. But a week ago I realized that something is wrong. I have a strong feeling that she likes me, even though she said that she already rejected me before and I don't have any reasons to think so. I really feel like she likes me, and I am aware that I have no actual reasons to think so. I have a strong, delusional idea, which was bringing suffering to my life for half a year and still does. Even with facts and logic involved, this feeling doesn't go away. This is an actual obsession, and I'm genuinely scared because of it. It affects the way I think and sometimes even my decisions. 

So what I need here us to know if I am mentally ill. All these factors - trauma, insomnia, apathy, regular panic attacks/sensory overloads, suicidal thoughts and heavy delusional obsession that affects my thoughts and decisions - almost of this in a spam of 5 months... This really looks wrong to me. 
So, the masterminds of Reddit, please let me know if I am mentally ill and how should I deal with it. Please consider that, although I am an extravert, I am awful at talking to stranger adults, and there's no way I can verbally explain my situation to a therapist. I would really appreciate your help.