It sounds like you recorded it with something bad going on and there’s no real way to fix a recording like that.
In my experience, once I’ve butchered an original recording’s sound quality, there’s no fixing it. An example: last summer, I recorded a live mix to my external digital recorder but didn’t take the time to check for clipping because of time constraints. When I got home, I realized that the whole 4-hour mix had clipped peaks all the way through. I even ran it through Platinum Notes but it still sounded bad.
It’s all about using good high bitrate source songs then recording them to wav without any clipping. I use auto-leveling in my software (every software has that feature) then I may use audacity to individually tweak songs that weren’t leveled enough by the dj program, after the fact.
I would just toss your mix and re-record it after you’ve figured out what’s wrong. After recording it to lossless wav, you can make tweaks in a DAW then rip to a mp3 for posting/sharing while converting the original lossless wav to smaller, but still lossless, flac for archiving.
Lastly, I like Platinum Notes just for audio leveling. I turn all the other parameters off because, at the end of the day, it’s really garbage in-garbage out.