Are you due for your period? If not, it sounds to me like fertile or EWCM (egg white cervical mucus). Most likely mixed with semen - that would explain the large amount.
definitely sounds like pretty classic egg white cervical mucus (i.e. fertile mucus)!
A good way to test is to stretch it between two fingers (sounds disgusting I know..). If it is your fertile mucus it should stretch quite a ways. Sure sounds like that is what it is though...happy bd'ing and good luck!!!
Oh, and no worries here about tmi or embarrassing questions...you should read some of the things I have asked/posted about..lol.