Leaking into my underwear?

Hey, so this is my first time posting something and I'm a little embarrassed, but I do need to know more...

For some reason, since my period started (about 2 years ago), I am constantly randomly leaking... I don't know what... into my underwear. Sorry if this is a little graphic but even if it's just wearing my underwear for 4 or 5 hours, there ends up being like a wet sort of spot or stain thing when I take it off. I'm still a virgin, and don't really feel "aroused" by anything in particular, so I don't know what it is. I thought it was common, but it was annoying, so I tried to Google ways to stop leaking(?). It seems kind of un-natural to me now.

If you can, could you tell me (1.) what I'm leaking, (2.) if it's normal, (3.) how long this should last, (4.) how much, if it's normal, I should be leaking, (5.) a possible reason why this is happening, and (6.) tips on how to make it stop please?

I would really appreciate it if anyone posts an answer to any (but preferably all) of the questions. Thank you so much! (and sorry for the long post, I'm impressed you made it all the way here!)