tears

I just feel like I could cry, the tears are there, just behind my eyes, my eyes stinging with the start of tears, but they just don't want to come out. I'm not entirely sure why or the cause but its there and its not a nice feeling. The last time I felt tearful similar to this but worse at the time, was when I hit my lowest and had to have time off work. Its strange because I don't feel anywhere as bad as I did then and I have so many other things that are better now, but its there, just sneaking a look, behind my eyes. There's also the anxious, worked up,stressed out, and easily annoyed, which could be the cause of  the feelings but also could be part of it.
Everything feels like its going wrong and the smallest thing feels huge. If I comment to someone, that there's a problem with something I'm dealing with, I don't get the answer or reply I need, but is this because of how I'm feeling or is it how I'm dealing with it and reacting to it or is it that they don't care, am I just "complaining again".
I shouldn't feel this bad its only work, but I dread going in the morning, feel overwhelmed soon after arriving and feel the weight of it long after I've left. Why do others seem to have it easier? why are others seemingly allowed to make mistakes? why do I get stuck dealing with the issues? and why do I allow it to bother me.
Sometimes I just think, if the tears could come out I would feel better, maybe letting them all go would help, but would I be able to stop?. They wont come when I need it most, it always seems to be at an inconvenient time or for something less important.
People say it's only work, I say it too, but it takes up such a big part of the day, not just the 8 or so hours your actually in work for but if your dreading it beforehand, its exhausting you while your there, and worrying you after you've left it fills up so much more.
It may not be work though it could be something else, maybe I'm just not doing as well lately, maybe I'm tired, or worried about something.
Just as I was feeling better, its come again, I am handling things better, how does it jump out and still catch me unawares.
One of the frustrating things is not being sure why, I'm sure I could feel better if I knew why or where it was coming from.
I'm sitting here trying to make sense of it, the only time I've not felt tearful since I got up this morning was the hour I was teaching my Zumba class, and maybe half an hour after but by the time I was driving home it was there again. I then worry about feeling that way again, and it makes things worse. It generally helps to write about it, it either pushes me to face the feelings or by writing them down it gets some of it out of my head.
So off to bed I go trying not to be too hard on myself for not feeling so good.
Tomorrow's another day, fresh morning and a chance to feel better and different.