I feel so lonely and I don’t know what to do

I have always been a very extroverted person. I don’t mind going up to people, talking in class, or trying to make new friends. I know my personality type isn’t everyone’s favorite, and I have often times been told I am being “too much”. I slowly become more introverted after this and made it really hard for me in to speak up about what I’m feeling. Well recently I started college and hang out with a small group of friends. This includes my roommate, her boyfriend, and our mutual friend. My roommate has been spending almost every night at their partners place, and I rarely see them. I had been a little upset about that, just cause I don’t love being alone all the time, but didn’t think much about it. Well roommate and mutual friend have been hanging out a lot more and I had been kinda feeling left out. They have all these inside jokes that I just don’t know about, and when I ask they just brush it off. It hadn’t been that big of a deal until this point. Yesterday, roommate, mutual and I were kinda planning a shopping hang out soon, and I was really looking forward to it. My roommate texted me today, asking if I wanted to go get food. We go to the dinning hall, and we are just kinda talking about what we had planned for the day. I told them I was going to probably go to the gym then see what happens. They said they was going to go shopping. I asked if the wanted me to come with, and she said “no, because I was going to the gym and that she was worried they would get distracted and spend a lot of money”. I said okay and moved on. I went to the gym, they went to store and life was fine. I leave the gym and check my roommates location and see if they were home. ( I have both roommate and mutual friends location.) When I looked, I noticed that mutual and roommate were together. This wouldn’t have bothered me so much if they hadn’t said that they wanted to go shopping alone. I sat in my bed crying because I feel like someone they don’t want to hang out with and just do because they feel bad. I don’t have a ton of friends and don’t want to lose the friendships I have now with them. I’m scared to confront them because what if I’m just crazy. I don’t know what to do or how to talk to them. What should I do?