Hi Jenna.
Was just cruising the forum and come across your post,
The first section of the track was punching my speaker cones, Lots of attack and loud.
Second section of the track was a lot lower in Volume and perceived loudness.
If I am telling you to suck eggs here, then please tell me to do one.
Before you start, Make sure your tracks are balanced in volume and loudness. but mix out to about -6db on your output meter.
Then to finish add to the master bus. A compressor, with just a little ratio. 1:5 Long attack time and a quick release. (Hope that makes sense)
adjust the threshold until you get just about 1-2 db of gain reduction.
Then add a limiter to bring up your final volume to around -1db.
This should level out your track a little,
Soundcloud only plays back a 128k MP3, so its not great.
Hope this helps
Prob a million ways to do the same but it seems to work here ok.. good luck.