Dead Spiders and Flying Nuisances

So recently since it has been getting warmer the flying bugs have been coming back. Somehow they get in my house (I suspect they wait around my front door till I come home everyday and swoop in once I open my door) and are annoying as heck. I just keep my pink slippers on the floor, one  in the kitchen and one in the front room, to be on hand in case I see one land so I can swat it. Also, when I am sleeping I get woken up by buzzing around my head in the middle of the night as one of the little nuisances tries to attack me in my sleep. So then I pull the blanket over my head, only to start suffocating with the lack of fresh air. It has been a rough couple of nights and the battle wears on.

Then there are these weird occurrences of dead spiders. At first I called them huge, but as Marisa pointed out to me, there are much bigger ones here, so I guess I am left calling them medium sized spiders. Anyway, I have found them dead in my house. I never see live ones in the house, only these dead shriveled looking ones that are about the size of a nickel without the legs spread out. They are just in a ball, dead, on the floor. The first time I found one I was stepping into my shower, and I almost stepped on it. It was just dead there on the shower floor. Freaked me out. Had no idea where it had come from. This last time I was walking to my front door and it was right in the middle of my hall way. I mean, I guess I can understand if a spider dies against the wall or in some corner or hidden place, but both of these were like in the wide open, where I step often. What is with that? And where are they coming from? And why do they just die in the middle of the floor?