Difficult to find the humor when feeling so bummed

Sigh, Monday is here and I don't want to be sat here. Air-con blasting into my face, blowing into my eyes, my colleagues sat by windows have all their blinds shut, a dark, orangey dinge to the air. Just, so de-motivating and uninspiring. I feel so old. That familiar feeling of previous years is returning, I just want to get out.
But I can't, not now. I can't afford to do anything rash, eventhough I want to. It's my mood, it has to be hormones, i've supposedly got another 4 days of this to go, I don't remember it being this bad in the past. Everything hurts, I'm angry, emotional, sad one moment and happy the next. I just feel...worried again.
We had a little back and forth over the weekend which was nice, but it was nothing hearty, not like it usually is but then I wasn't really expecting this. He's been busy. It's nice that he went to the effort to even drop me something I suppose. He's going to call this evening which i'm looking forward to, but i'm not sure when I'll see him next. I hope it'll be soon, but who knows. I'll let him be the one to set the wheels in motion in that aspect. I'm so nervous about his birthday, I don't know why. There's just so much going on in my mind and I'm struggling to focus on anything positive. The not knowing what we are, the not knowing if he really gives a shit, the gift - it's likely too much, might make things awkward, the feelings I feel which I've let get out of hand...just, I've really screwed myself over. I've been trying to do too much.
He's too good for me, this is my fear, him realizing this and him finding someone else.
It's like these daft ideas and thoughts enter my mind when I haven't seen him for a week or more. If i'm lacking any sort of reassurance, that's it. Forget about it. Game over. Worst case scenario will be happening, it's all prepping for a disaster heart-break situation. Why? Why do I torment myself like this?
Well. The ball is in his court. My sitting here, stewing over all this nonsense certainly isn't going to prevent it from happening, nor is it going to make it happen either. I'm just going with the flow, going along with how the cards are dealt and hoping for the best. That much is true, in all of this. I'm sure all will become clear, and perhaps one day i'll look back on all of this and laugh at myself for being so dramatic. It's difficult to find the humor at this point, though. I shouldn't rely on someone else to make me feel happy. 'Never let your happiness depend on something you might lose' yeah, easier said than done...