Concerned possible miscarriage

Im just 4 w 5 days, and had some red blood last night. About enough to wipe 3 times. Then brown discharge since. (So 15 hours of blood then brown discharge) Its not a whole lot, but has me concerned. As I have miscarried before my first pregnancy at 8 weeks, and this is now only our 2nd "confirmed" pregnancy in 2.5 years. Coukd it be just a short period? Or more likely miscarriage? I have my 72 hcg blood draw in the morning. Should I prepare for the worst and hope for the best? Anyone experience this before?