My UFO sightings

I've mentioned this in other posts, but here it is: a detailed description of most of my UFO sightings. So, it's worth noting I'd started watching the X files a while before I saw these, but had always been interested in ghosts and stuff. I must admit, I don't really care for nor believe in ghosts or spirits, to be honest. Though I do know someone who's had multiple experiences with shadow people, and someone I know heard weird screams at night that they think is a Banshee. I dunno when it started, but occaisonally after watching TV at like, nine or ten o'clock, I'd go out to the backgarden. I did hallucinate a thunderbird vaguely out there once, and might have hallucinated a Mothman [though it might have been real, I'm sure nobody is really too interested, though], but these were real, and other people saw them. So I don't remember when it started, but I started to go out to the garden every night and wait a few minutes since I wasn't allowed to stay out for too long. The first important sighting I had was when my mum was in the bathroom and I was getting something from the fridge. I opened the door after noticing something weird, and I saw something that looked like a shooting star, but it had no tail, was too slow, and moved straight. I shouted at my mum to come and see it, and after about twenty seconds of shouting, she did, and we both saw it slowly drift away. The second important sighting was when everyone else was in the kitchen, most others saw it, but I saw the most. During the period I saw these things, I noticed more millitary helicopters than normal, and they flew lower than normal. The first of the night was when a weird star-looking thing moved through the sky, the same way the other one did but in a different place. A bit later, both my parents and me all saw another one, but while my parents didn't see it, I saw it zigzagging the tiniest bit as it moved. It was in the same place as the first one. There are plenty of UFO sightings where I live, so I don't think there's a connection to the Bigfoot I saw. Does anyone have an explanation for this? Why it only happened during a small period of time?