Constantly worried about my PC?

So basically, I built my first PC about a month ago, and I'm always uncomfortably worried when using it. I feel like I didn't do a very good job putting it together, I mean, I feel like I could've been a little less reckless, maybe worn anti static protection more of the time etc. Ever since it's been built really I find something to worry about, probably because I built it myself and it just seems odd how I'd be able to do such a thing correctly. The main things I'm worried about are : The motherboard, the PSU, the graphics card, and the hard drive. My graphics card is quiet enough but some times I worry when I hear certain noises, wondering if they're normal. Installing the graphics card wasn't that easy either or as smooth as I believe it should have been. It slots into the PCIE slot alright, but it has quite a lot of ability to move about even when doing so. I had to sort of jiggle it about to the left just so it would line up with the mounting holes on the case. Wondering if this is a fault with GPU or motherboard, or normal. My hard drive is probably the noisiest component in my PC. I mean, some times it can work REALLY hard , usually when I'm not really doing much, but when gaming and typing this thread, it's silent. It makes quite a lot of clicking noises when working, seemingly normal clicking noises, but it does so quite frequently randomly. Also there is a noise coming from something which I would assume was the hard drive when starting up the PC. First of all I hear a sort of "berhh-berhh" noise, sounds like a wall of light from the game Dishonored, or like when something is powered by whale oil. Then I hear a sort of rattlesnake sounding noise which I am almost positive is the hard drive. I've had no problems with booting so far, just those noises which I am unsure of. HD Tune says my hard drive is fine though. One of the most things I'm worried about lately is the LED on my power button has been flickering/dimming randomly lately, but I haven't seen it doing it during this session of it being powered on, which means it's getting better, which makes me kind of worry worse, as I originally thought the light must be dying. Now I'm very worried that it's the motherboard or PSU at fault, which even though this is small, makes me wonder if it'll arise to greater problems if those two components are at fault. I've plugged it in fine, so it's not that. My case is the Corsair Carbide 300R by the way. My PSU seems fine to be honest, I'm only really worried that something may be wrong with it through the power LED thing. And my motherboard I'm just really worried about because of the graphics card having movement when installing, and also the power LED thing. None of my components have really FAILED as such, or show any major signs of being bad, but I just wanna get this out of the way because I'm really worried my £800 build will just, blow up. I think it's possible if something's wrong with the PSU or motherboard? I'm also known to be a bit paranoid and overly worried, and probably because it cost a lot of money and I'm afraid of losing it, but I really want FULL RESOLUTION to these things I'm experiencing and it's killing me, not being able to even use it without feeling uncomfortable.