There are a number of resources that can be very useful to your playing!
Imslp is a website that has a ton of public domain scores and sheet music, including original manuscript copies. The website is especially useful for finding classical music!
https://imslp.org/wiki/Category:For_trumpet
If you want some pop music, musescore.com is for you! It has a massive selection of music of all types, trumpet included! https://musescore.com/sheetmusic?text=trumpet
Youtube.com can be a great resource for not only finding performances to the pieces you might be practicing, but it can be a great hub for finding tutorials and guides to more specific aspects of your playing.
Don’t fret if you think that you aren’t progressing fast enough, learning any type of instrument WILL take time. Keep pushing and it will be rewarding!