My dog's top eyelid is swollen her eye is red but it doesn't seem to bother her any ideas?

My dog is a Blue Nose American Bull dog, and all of a sudden she has a swollen eye lid only the top is swollen. The eye itself is a little red and it looks wet under the eye there are gooey eye boogers but not much and i cleaned them off. I am really worried because it was not like that this morning. Its swollen to the point where she can open her eye a little bit. I am not sure if she scratched it, something got in it, or if its just a bug bite. She is also pregnant and i am not sure if the pregnancy can cause it because i don't know a whole lot about this kind of stuff and we don't have an emergency clinic around here that i know of. I can take a picture if it would help? I am going to call the vet tomorrow but i wanted to know if anyone has had a similar problem and if there is anything i could do now?