Yes, it sounds to me like dissociation. It's a bad state to be in. I can tell you what I do when I'm in that state, and how I get out of it. It's a good sign that you recognise that you are dissociating.
When I recognise that I'm dissociating, I stop and observe myself and my emotions, my bodily sensations etc. It helps to move my body, to get up and walk around a bit, while focusing on how my body feels. Accept what I'm feeling. That I'm in a dissosiative state, and that I'm sad for a reason, all though I don't know why. Lately I've been able to do this and come back to myself rather quickly. My body is in the here and now, even though I'm dissociating.What does my body need? How does it feel? I observe it, while I move around a bit. Moving my body, being active (in a calm way, like walking carefully around, moving my arms a bit, focusing on what it feels like. ) I need to come back to my body. I also focus on things around me. I open a window, I take in the smell, I walk around and feel the sensation in my body, I name some things around me. It's important not to stay put. The body needs to move.
If you were to go on that trip with your boyfriend, I would try to recognise the world around you. Listen to the birds. How does it smell, how does the ground feel under your feet. Don't interpet, don't be afraid if it's all a blur. You will come back again. I find that coming back to my body first is the easiest way. The other day I had a moment where I realized: Huh, I'm hungry! I could eat! And that was all I needed to come back. It made my body come back to the here and now. Not right away, but gradually, as I allowed my body to get what it needed. I need to search for my bodily needs, it doesn't come naturally to me. And for each time, I recognise it sooner, and I avoid dissociating.
You say you are tired and that you keep pushing yourself. That is something that might take you further into the dissosiative fog. You are no longer in contact with your bodily needs here and now. You are sad and tired. It is important to accept that. Your body is telling you what it needs. The minute we numb or run away from a feeling, we are not fully present anymore.
For me, I am recently learning how to stay in the here and now, how to avoid dissociating, how to recognise it the minute I'm starting to lose track. Whenever I'm feeling a bit blury, tired, restless, I check with myself. Where am I? Where is my body? Am I hungry? How long since I ate? Am I tired? Should I lay down a bit? Am I sad? Am I mad? I have to remind myself to feel, because I'm so used to going on autopilot, pushing myself to to all the things I feel I should be doing. But by doing that, I will sooner or later become dissociative.
I don't know if any of this was helpful, but I hope you will find your way back soon!