Drugs can numb the feelings associated with trauma, thus, in the short-term, making it easier to deal with. Now that you're clean, the feelings that the drugs were anesthetizing are coming up for what sounds like the first time. This happens for lots of people after experiencing a rape- the symptoms don't start until sometime later, catching the person off guard. While this is certainly unpleasant and even scary at times, it is normal.
There may come a time that you want or need to talk about your rape but that doesn't need to be now. Sometimes it helps to work on calming your anxiety (and the nightmares that come from it) first. There are many ways to do this- sometimes people use a medication to help relieve anxiety and/or promote sleep. For people who prefer not to use medication, learning things like deep breathing exercises, yoga, meditation, and/or progressive muscle relaxation can help manage anxiety and relax your body. Once you learn how to cope with the anxiety that comes up for you, it might be easier to think about going to sleep and, someday, talking about your trauma, as you will likely feel more able to manage whatever feelings could come up.
I hope this is helpful.
Psychologist
Doctorate in Clinical Psychology, 10 years experience working with individuals, couples, & families