Nightmares of sorts

I have been having trouble with the same situation off and on since I can remember recently it's gotten worse. I will be in a state of being semi awake and semi asleep but still feel awake. I don't know how to describe it sorry if it makes no sence. Any way over the past month I will see this person a man I think in a shadow like form watching me. Never moves never says a word. However my reaction is always the same I wake up screaming no no no no and my heart is racing. Normally my husband or dog wakes me up in the middle of it. It doesn't seem that scary thinking on it when I am awake but my reaction to it is always the same. The room looks exactly like my bedroom making it seem at the time very real. Needless to say my poor husband and dog get very worried and it is annoying to say the least. Why it happens so offen now I have no clue. It use to be like a twice a year thing now its almost two or three times a week.