Heartbroken Over Unloyal Friend

So my first year in college, I met a girl named Kelly and we instantly hit it off. We were inseparable and did absolutely everything together. I've had troubles in the past with bad friends so I was thankful I finally met someone who worked equal parts at the friendship. We had 2 other roommates that we were also very close with but this past year we had a falling out with them.

We started to branch out more and met another girl named Lacey who is pretty well-known on our campus (she's super sociable, a really good person & friend, and know's everyone) We hit it off with her and decided to room with her and her best friend the following year. Over the end of the school year Lacey and Kelly started to hangout more because they had more free time than me and I was always studying. They got closer and closer and I started to feel like i was fading more and more into the background.

Whenever Lacey would do thing s Kelly would follow, even if I asked Kelly to do something with me she would pick Lacey over me. I started to feel like I was becoming friendless and getting very self-conscious. Because of it mine and Kelly's relationship became strained and I stopped putting in effort. She's still my bestfriend but I feel like she would pick Lacey over me in a heartbeat and I'm now rooming with these girls next year- my so called "best friends" -but I feel like I'm not totally included and I know it's only going to get worse as time goes on. I've addressed these issues with Lacey, and being the good friend that she is,she completely understood where I was coming from and promised to try to include me more.

She also said that the only reason why her and Kelly have been hanging out so much is because they have the time too while I don't. This was understandable and I respected her for her honesty. I didn't address these issues with Kelly though because I feel like being friends with Lacey is a competition for her and she is never completely honest with me. She'll lie all the time about hanging out with Lacey or other things to hide it from me because I feel that she doesn't want me included. Don't get me wrong, Kelly is a really caring person and also a great friend but I feel like she has deeper issues (self-harm and lying problems) that have gotten worse over the years. Adding to that, I got accepted into the program that we both applied for and she didn't which only added to the strain.. I felt like things really got worse after that happened. Also, the program is challenging so I know next year I will constantly be studying while Kelly and Lacey hang out.

I just don't know if I should keep working on the relationship with Kelly or what my next move is. I do not want to lose them as friends we all have a great time together but things with Kelly have been making me feel constantly uneasy and i just feel friendless. I have been nothing but a supportive caring friend to her and I'm devastated by this because the same thing has happened to me in the past. Also noted, Kelly is a quiet person who doesn't really speak out on her emotions so it's hard to talk to her about these things. Please help me I have a heavy heart over this and any advice will be appreciated.