Am i over-reacting or is there something out there?

Last night I needed to go to the shed to get something. Before I went outside I turned on the outside lights and suddenly felt scared, usually I am okay to go by myself but for some weird reason I was scared. So... when I went outside the temperature felt really really warm, there was no wind and it was really quiet. The outside light wasn't working, so I went back inside checked the light switch and it was on. So I decided to run to the shed while it was dark and all of a sudden the light came on. On my left side there is the backyard and I hate looking in that direction I had the goosebumps and felt like something was right there. I went in the shed turned on the lights, maybe 10mins later thats when the lights flickered. I turned them off, had the goosebumps again and ran out the shed. Luckily the outside lights were still on, I made it back to the house and on the deck my cat ran up to me and my goosebumps were gone.