Yes to what STacia said--
Also, not sure how long it's been since your birth, but it may be possible for you to request a Kleihauer Betke test to see if there are baby blood cells in your bloodstream. You might want to talk to a lab that does the KB, and find out how many days after birth they might still be able to accurately assess presence of baby's blood in your circulation. If it is believed that the KB test would still be helpful at this point, that is one way to find out if sensitization occurred (whether or not antibodies have been made yet).
There is sensitization and sensitization...that is, not all sensitization is equal. Some women's immune systems react 'more' than others in terms of creation of antibodies...especially w/a first baby following sensitization (as S has said). Along with u/s to check on the next baby, there is also the option of serial antibody tests for you during a next pregnancy (having the antibody test every few weeks during pg, to determine if count is rising). Although there are no hard and fast rules about how a baby will be impacted by the presence of maternal antibodies, there are some rules of thumb concerning the number of antibodies present in mom's bloodstream during a pregnancy.
Skipping the details here, basically the serial antibody tests can help you figure out the degree of risk for your baby: low antibody count most always means little to no harm comes to baby, high or gradually increasing antibody count indicates increasing risk. However, there really ARE no hard and fast rules--a high antibody count does not always mean that baby will be harmed. NOt only do women react differently/individually to sensitization, so do babies. HIgher antibody counts *might* mean more harm to baby....and might not. This is where u/s comes in, to help see if baby is growing properly. There is a midrange of harm, as well--some babies are anemic and jaundiced at birth due to the antibodies' attack of their red blood cells (which impacts their intrauterine growth), but can be effectively treated for those things without too much ado after birth. Being sensitized, and baby being effected, in other words, does not always mean 'the worst'.
It may be too soon now to use the antibody test to determine if blood mixing occurred--yes, early studies were done on incarcerated women who stayed in the hospital routinely, for exactly 3 days. Based on studies of their antibody status in that time, it was determined that it takes 'more than 3 days' for maternal antibodies to form. No one really knows HOW MUCH LONGER than 3 days--it is assumed medically that if RhoGAM is given by the end of 3 days, then it will be effective in preventing sensitization.
However, you might get an antibody screen in a few months, or maybe later, at the point when you feel you are ready to ttc again. Knowing you are clear of antibodies will certainly clear the way for ttc, right? If you are making antibodies, then knowing how many are circulating can help you to determine how high is the risk to another baby. While there is no way to know in advance whether or not your antibody count will climb (or climb drastically) during pregnancy, at least with a prenatal screen you see if it is already high or not.
So...maybe investigate whether or not the Kleihauer Betke is still an option--and don't wait to find out, do this now. Otherwise, the antibody screen at some point later will probably help you in decisions about ttc when you are ready.
ANd remember that it is quite possible that you were NOT sensitized at all!
Sorry that your birth was chaos and trauma for you! Best wishes in sorting this out--and in having a better birth if there is a 'next time'.