Hello, just to start, i have very irregular periods and my last period was august 22nd-27th. i had protected sex on the 27th and then again around the 4th. on the dates sep. 10-13 i noticed very dark brown discharge and cramps. is it implantation?

Conception occurs within day or so of the sex. It takes about 3 weeks for the embryo to make enough HCG for a positive pregnancy test. Blood test may be done a day after a missed period. Home pregnancy tests should be done 4-5 days after the missed period. If the result is negative repeat the test in 4-5 days. Use first morning urine and follow instructions for the test carefully.