Please, please, please get a vet, Horsecrazy.
I have a mare with ERU (that disease was mentioned by CCH) and it's the worst. Watery, slightly puffy, eyes are basically her only symptom.
Unfortunately, because her previous owners assumed that it was "nothing" and because I assumed it was "nothing", she's now nearly 28 with very little vision of any kind.
Each time her eyes water and get puffy, she looses vision. The only difference is how much vision she looses and that is directly related to treatment vs no treatment. In her case, the longer she goes without treatment, the more vision is lost. Treatment is super easy, just giving her high doses of bute for a few days as well as using an eye ointment prescribed by the vet is enough to stop an episode (she does have to be on daily "medication" as a preventative though). If she had been appropriately diagnosed a few years ago, she would still have the majority of her sight.
But since no one thought to think about ERU, well, here I am. With a horse that can't be with other horses due to the danger they pose to her, on daily expensive medication, with special fencing needs since she can't be behind an electric fence, etc.
I'm especially sensitive to this because last spring, when my mare lost most of her remaining vision (she went from probably 60-75% vision loss to 90-ish% in 2 days), I thought that her itchy, watery, swollen eye was not really something to be too concerned about - figured she had hay in it or something. So I gave it a day and when it didn't improve, called the vet the next day. By that time, once we started aggressively treating her, it took her a full week to recover. And even then, the sight was gone.
I know it's not specifically "my" fault but I still feel guilt, like I should have somehow known and that if I had she would still be seeing. I just don't want you to be in a similar place a few years from now.
I don't want to scare you but eyes are not something to mess around with. Please call a vet.