thick discharge

my period is 10 days late, i took a pregnancy test on day 6 and it was negative, since then i’ve have no appetite, lower back pain, mild stomach cramping and feeling exhausted. when i wipe recently i feel a lot more slippery and then this happened. no odor, no itching, no pain or discomfort in peeing or my vagina. been with same partner for 2 years so not a std, any advice would be very helpful as i’m 19 and don’t want to talk to anyone else yet.