All right, from your words, I know you have got something tough. Because , as a matter of fact, subconjunctival hemorrhage is one of the most serious problems with our eyes, which is resulted from a wide variety of causes, such as high BP, bad use of eyes, traumas, drinking, etc. Just try to get some cold compress and then hot compress 3 days later. Of course medical help is quite needed for you.
The subconjunctival hemorrhage is a serious eye disease which means that your eyes cornea has the problems. It is mostly caused by the lots of use of eyes in front of the computers because of work. The high tension and great stress may cause it. If you have the good rest and keep the healthy diet, it could disappear soon. However, I still suggest you to go to see the doctor to get rid of the infection at the eyes fully.
No,you are not likely to know it or feel it without others telling you or seeing it in the mirror. Subconjunctival hemorrhage is equal to the bruise of your eyes which is harmless in most cases and often disappear itself. However, it may be a sign of serious brain damage like skull fracture. If you feel any discomfort besides red spot in the eyes, you need to see a doctor.