Bottom part of my eye is red??

Yesterday morning it felt like I had something in my eye and I didn't see anything. I kept checking throughout the day and nothing in my eye. I was at work all day, didn't touch my eye, or even rub it. Later in the evening my right eye got red. My eyeball feels sore, scratchy (like I rubbed it too much which I didn't), kind of itchy, always feels like I got something in my eye. Looks like the redness isn't as bad tonight. There is no swelling, I do get a little teary, that's about it. I'm a little worried, what the heck is wrong?