Going forward but getting super emotional.

I am on my 78th day, I have no urges or whatsoever, the previous streak was 150+days, I think I have cracked the code for me how to keep myself clean. I was using tinder, but I realized it only triggers me a bit, but not in the way that I want to relapse, but you feel that it messes up with you, so I stopped using it. I am more confident, I can say what I think with no problem, it is easy to talk with people. I workout, study a lot, but lately, I don't feel in my own skin, I feel super serious, If I don't have anything to say, I just stay quiet, okay, but what is strange in it? Usually, I am a loud person, I can't keep myself quiet, but now I just stand in a group of people and actually listen and keep myself quiet and my friends ask me: why are you so quiet/serious?
- I just don't have anything to add or say... (Usually I always had something to say).
With other friend group and people, I feel like no one cares if I am there, I write a message in the group, no one even reacts, but when I left the group, eventually everyone was interested why I left, is everything okay, I really appreciate this, but I start overthinking more and more often. I was/am dating a girl, I am not sure what is going on now...We talked a lot once a week, like from morning to the middle of the night almost non-stop, for the first time I opened up for a girl in years, I enjoy her company very very much, we have similar interests and life philosophy, but she told me that she would never like to marry, this hit me like a truck, I feel like I am swimming against the stream and this is killing me inside, I hate that my engineering/sciences course takes so much time of me, I offered her to meet this week, but I still haven't invited her, I will invite her tomorrow. This hard study course drains me, the girl of my dreams is stuck in my head, I feel empty without her, I start feeling depressed, when my friends asked me why I left the group, I was just hit by insecurity, I didn't want to tell everything that is on me, I just wanted to leave this conversation as fast as possible, this is weird for me. I just feel empty, sad, I feel like I am losing control of everything in my life, I am losing the grip. When someone just goofs around and makes jokes, I just don't find things like these funny anymore...I want to be alone, but I want to be loved at the same time, I hate this dilemma...