Mastering question??

Hey all,
I'm noticing that listening to the final product in the daw and uploading it to SoundCloud, dropbox etc everything sounds good and loud and clear then when i export the tracks and throw it in rekordbox, its so quiet in comparison to other tunes and doesn't compete at all with similar tunes. the waveform shows that its super quiet as well yet when i boot up spotify and listen to my track in the daw, other tracks similar sound the same loudness.

My question is,
Is this a mastering thing or an exporting settings kind of problem?
because my mix is perf and all the levels are nice. just lacking the loudness and i am not skilled enough yet to be able to master my own stuff to a professional level as when i try boost any kind of loudness i lose clarity. and im also broke asf so i cant afford to pay someone to do it as im not sure if its a mastering problem or not.

here is the track in question - https://soundcloud.com/winxnz/original-don-winx-refix/s-bzADzxFBAZx?si=e5ae478ea3174016b0c7299302369773&utm_source=clipboard&utm_medium=text&utm_campaign=social_sharing