Uy mama, 38 weeks ka na at may spotting plus possible mucus plug, this really needs your OB to check ASAP, ha! Especially with the cramping and that reddish discharge, don't wait lang, call your doctor or go to the hospital para ma-examine ka properly.
A few of us mums have experienced similar things near the end, pero lagi kaming sinabi ng doctor na dapat i-report agad. Better safe than sorry, lalo na first time mo pa! Your OB needs to see what's happening, especially if may spotting involved, hindi kami pwedeng mag-confirm kung mucus plug o ano yan from a picture lang.
Samahan mo ng picture ang doctor mo ha, at ipaintindi mo rin ang cramping. Rooting for you, mama!