This is a good question.
Dreams can be tricky.
Just because you have a dream about abductions doesn't mean that you are being abducted. There is a certain quality to the dream if it is a repressed memory of abduction. Other signs would be multiple sightings of UFOs, finding marks on your body that appeared overnight and sometimes paranormal activity around your environment. Finding blood on your pillow or waking up with a bloody nose on occasion. If you're suspicious that you are an abductee, keep a journal of your dreams and anything else strange that happens to you.