(20M) Staying friends/classmates and working togheter with my ex (20F) is proving to be very difficult.

Long post ahead. Many important details though.

#Important information

Me (20M) and my ex (20F) are in the same department at university: film directing. This means that I will see her at every class we have, unless one of us skips that particular class. We also spend up to 10 - 12 hours at school and are part of the same friend group, meaning I will see her during breaks and on film sets aswell. Cutting all contact is not an option.

#Background

She broke up with me roughly 2 weeks ago. The reason she wanted us to break up for is because I let her down in a few situations, some regarding school, because of my depression. The final straw for her was when I called off meeting her on a weekend, having skipped university that whole week (I couldn't sleep at night so I'd sleep during the day, I texted her very little and barely answered the phone), because I needed to catch up on some personal university work.

When she broke up with me she told me she lost trust in me as a partner but not as a person. She also said she wants us to stay friends because we were very good friends in the past and had good chemestry (everybody, including our teachers, thought we were dating before we started dating). Also, because we're in the same department, we're sometimes required to work togheter, communicate and share equippment, and she didn't want to make that awkward.

She told me the breakup is very difficult for her because she still loves me but the relationship ended up doing her more harm than good. She also told me she's still attracted to me phisically which makes it all even more difficult for her. She finished that encounter saying that maybe one day we'll be ready to be togheter again.

I'm pretty sure she tried to hint at wanting to hook up after the break up (we were hugging thightly and her words were: "I think it'd be easier for us to navigate this if there wasn't so much sexual tension between us") but I wasn't really sure at the time and didn't want to break any boundry.

To be honest I still love her. I really care for her and I'm still very much attracted to her but I wouldn't want to make her more unhappy given the circumstances.

I 100% agree with her reasoning for breaking up though. I definitely need some time to get my shit togheter and focus on work, mental and phisical health, uni and all that. I got deep into my problems and ended up taking her for granted. I didn't pull my weight in the relationship.

#Current situation

Staying friends and keeping it cool as classmates is proving to be very difficult, both looking at my behaviour and her behaviour.

The days after the breakup were kind of okay but she was visibly on the edge. I'd talk to her, call and text the same way I do with the rest of our classmates and friends but she told me talking to me hurts her so I stopped.

I try to joke around the same way I do with the rest of our friends but she's not having any of it. I can feel the tension in the air during breaks or class or on the film set.

Sometimes I notice her looking/staring at me during class or outside, during breaks. We're very much aware of eachother while existing in the same space.

Some days I notice her myself, I can sense she's feeling bad or if there's something up. Sometimes she looks really good in an outfit and it takes some effort to not keep glancing at her.

Sometimes she talks to me, sometimes she dosn't. Sometimes she's playful and sometimes she's cold. Whenever I see her I feel like shit. I keep remembering I made her unhappy. I keep remembering the good times and how I fucked it up.

#Yesterday

Yesterday we finished some big projects in collaboration with the other departments so all of us went to a nearby restaurant to celebrate. I arrived later because I had to pack some stuff at school and when I arrived she was clearly drunk.

She was having a great time though, especially with one guy from the light design department, who she worked with on this project. They were talking a lot and laughing.

I was happy to see her happy but also felt like crap because this other guy (good guy, I know him, nothing personal) was getting all her attention.

We didn't interact at all that night, we'd sometimes catch eachother glancing at the other but we didn't interact. Earlier that day I made a joke with her (something along the lines of "doomscrolling again instead of finishing that script?") which pissed her off.

At the end of the night her, that guy, and 2 of our other girl classmates left with the same cab. I again felt like crap.

#Today

Today she called me to apologize for ignoring me yesterday and said it was because of that joke. I said it's fine and apologized myself. We left it at that. I skipped class today to catch up with an extra assignment.

I really don't know how to handle this situation. On one hand I still like her a lot and would love for us to talk more often and go back to that playful chemestry we had in the past. On the other hand I understand it's been only 2 weeks since the breakup and we're both proccessing it all. I know I have to focus on myself and I don't want to break any boundries or make her more unhaply but her hot and cold behaviour confuses me. Any advice would be appreciated.