I (19m) need help with my gf (19f)

Hey guys maybe some of you have some sort of an advice or help. Ive been with my gf for about 4 years. We both know what comes with being together at a young age. I’ve seen a ton of versions of her and loved every single one of them as she has me. Recently it’s just been hard we’re long distance and she’s in California I’m in Texas. I’ve seen her a couple of times cause I went to visit like 4 times since January and she came in the summer. Recently we ran into this problem where she was being really distant. She would tell me that she didn’t feel good and she just needed a break from everything and she wouldn’t talk to me for days. I understood tho she has a really stressful job and her parents have never been the supportive type they give her problems even when she’s not home. But I couldn’t do it anymore and told her that I was tired of her disappearing and putting little to no effort at all into us and she told me she was sorry and she didn’t know what was wrong with her. She said that I’m so good to her and I treat her amazing and love her so she doesn’t know why she feels like she’s unsure about us. I told her that I can’t force her to do anything she doesn’t want to if she really felt like maybe I was holding her back from living the life she wanted to live or she just didn’t want to be with me anymore I was fine with that because my goal was to see her happy.

After we had that difficult conversation it was like she flipped a switch she started calling me every day like she used to and actually started acting like she cared. The only thing is that I don’t really know what to do like truthfully. Like I can tell she’s still thinking about what to do. But is it like a time will tell type thing. I’ve been enjoying everyday because idk if it’s gonna be the last.

Also why do you guys think that could happen in a relationship. Is it the type of thing where you can lose a spark in a relationship like after all this time. She’s my first girlfriend and I’m here first also. I like to think it could be a like also the way she was brought up like her mom and dad weren’t the type of people to show her how to love yk. Idk