when you are using pills if you miss two pills better to go for alternative method of contraception
for next one week,
brownish discharge and cramps could be side effects of the pills, they will usually subside soon,
as you missed two pills we cannot completely exclude the possibility of pregnancy
so you better consult gynecologist and undergo blood test
for pregnancy, if test comes negative, you can take anti-spasmodics for relief of cramps, and discuss regarding changing the type or brand of pills to prevent future problem.