macOS Catalina not allowing me to access full storage on my disc

My hard drive has around 90 GB on it, however Mac is only letting me access/detecting around 40, yet still somehow seeing that there are almost 90 available. I have tried googling around, however most issues seem to be related to the Mac incorrectly calculating the available space but still reading the correct total capacity. Has anyone encountered this issue before?

Edit: After running df -h it appears my disk is partitioned into multiple partitions. Adding up their sizes equals the correct 87 GB, however, each of them have only 40-50% capacity.

I fixed this by doing the following:

1. I ran diskutil list. Then from that list, I checked which part of my disk was the one apple was using in the GUI in my original question by checking which one's size was also 42.74 GB (Its identifier was disk0s2 in my case).

2. I ran sudo diskutil apfs resizeContainer [the identifier we retrieved above] [the size we want it to be, so 87G]

2.5 In case this does not work the first time, run diskutil repairDisk and try again.