I'm not sure about the seeing things, but your heart rate being up could be linked to why you feel scared. And it could possibly be sleep apnea. Waking up frequently may also be a sign of sleep apnea, though one does not have to do this in order to have it. A reason you may be waking up could be because your brain is realizing that you are not getting enough oxygen, and this causes you to wake up. Your heart rate being up could also be due to lack of oxygen.
Best thing to do would probably be to see a doctor, get tested for sleep apnea to see if that is it, or rule that out. Don't let the doctor make you think that just because you don't snore (if you don't) that you don't have sleep apnea. That is the most common symptom, but doesn't have to be present in order to have it.
Also, depending on which type of sleep apnea it is, or perhaps not even depending, a test may come out negative, when you may really have it. With obstructive sleep apnea, it has been proven that a single test is sometimes not enough, because another in many people has come out positive when the first was not. Good luck.
Actually, your heart rate may be up BECAUSE of your poor sleep. Constant awakenings can increase blood pressure. I went through this. Now the question may be, why are you awakenings so frequently. May be due to medications (they are frequently a sleep disrupter). Or, can be a sleep disorder (leg jerking repetitively, etc...) You may need to go to a sleep lab; may need to get a referral from your pcp.
I wish you the best.