Answer: Hi..little spotting and brown/sticky discharge during pregnancy, is normal, therefore, do not worry. Keep yourself hydrated, drink lot of water and juices. Also, whenever next you will visit your gynaecologist, then inform her about it..
Symptoms of labor, depends on individual to individual. I can tell you few such as cramping in regular intervals, with increased back pain, vaginal discharge colour changes, loose feeling joints, water bag bursts, stronger and more frequent contractions etc.