Mixer? \(; A ;)/

Actually, your mic quality isn't THAT bad o.o. Your voice is softer than the BGM. But that can be fixed.

What you can do is that, after recording your voice, noise remove your unwanted noise. I'm not sure how Audacity works because I'm using adobe audition for quite sometime. You can google it or have someone here explain it for you
Now, Adjust the volume of DIFFERENT PARTS of your singing that you wish to make it louder/softer.
Amplify your whole vocal recording to the optimum level where by your voice is not distorted ( When it exceeds the db line, then it's too much. )

Tip: Erm, when you scream, pull your mic away x_x. If not, your recording for the screaming will be distorted whereby you hear all the static or whatever it's called. There is no fix for distorted recordings ~.~

I'm no professional/expert. I'm just coming from experience so, forgive me if I said anything wrong .

Btw, you sound not bad XD!

Make sure you use noise and/or hiss removal.

I would also recommend using dynamic processing and then amplify as well.

And like Kago has said, when you scream try to put your mic further away from yourself.

If you need more help, google is your best friend.

Off topic: I LOVE "LOVE IS WAR" AND I THINK YOU SANG IT WELL <3
Hahaha okay back to topic.
I am no expert but I may be able to help .. maybe not x_x since I use adobe audition most of the time. (I use audacity last time though!)
I have a horrible and cheap mic as well, no noise cancellation, no condenser, no whatsoever except for the fact that I can use it to record my voice -___-
The worst thing that can ever happen is when I blow air into my mic, it is very difficult to remove those when you're cleaning the vocals. '

So one of the best ways to stop the blowing air thing and distorted high notes is to put the mic further away from you, and then amplify the whole track like what Cherysh and Kago said! It really helps in singing those high notes without distorting your sound quality.

Do you use noise, hiss and click removal? I think those are the most useful effects that can be used to clean your vocals
Maybe you can try hard limiting as well, limit and compress your whole vocal track since that it only reaches certain db. (I tried that once, it didn't really work that well for me but you can try )

One last advice: change your mic if you really want a good and full sound :X I don't think your mic is that bad though
Even if you have a horrible mic, mastering and cleaning your vocals is the key to make your recording sounds nice! Keep on working on it~

I think your mic isn't really horrible per se; your problem is more of a peaking and popping issue, which are the two things that are hardest to remove when mixing XD Like others said, to avoid this just make sure you're recording with the mic farther away or setting the mic volume on the mic itself lower (assuming it has that XD). As for popping, you can either make a pop screen yourself or just keep your mic at an angle so the p sounds don't enter directly into the mic. Another tip I'd recommend is putting a pillow behind your mic or recording in a closet if you're closet's big enough-- it absorbs a lot of the background sounds and reverb so the track comes out cleaner overall.

For gaining mixing-fu, also check out this thread persona posted- it's really helpful and covers loads of tips on how to make your mic sound better: https://ytchorus.forumotion.com/recording-mixing-help-f20/the-beginner-s-guide-to-mixing-audacity-t1687.htm