hey bro, try and blead the system. It should pump back up. If it does and looses pressure again then your master cylinder is bad. If it doesnt improve at all from bleeding, it could still be the master cylinder but no improvement after bleeding normally means that its the slave cylinder. Give it shot and if you need a hand, I can swing by on like friday. We have a long weekend.
When it comes to problems with the clutch hydraulic system, its always smart to replace both the master and slave. I know first hand if you have financial issues like i have in the past, diagnose and only replace that of which is bad. If you can afford it, replace both though.
Do you have a garage? If not, you can bring it by my place this weekend and use my garage to keep us out of the cold. Its up to you though! Just let me know bro! Best of luck!