Cycle length 25-26 days. slight blood tinged mucus/discharge on day 21. still waiting for period now day 24. no more obvious blood mucus. problem?

First, safe sex?: Check a pg test to be sure, if able to get pg, anytime your period is abnormal, in length, symptoms, or timing. Repeat in a week, if negative, and you miss another period, see your doc to find out why. Follow the instructions on the kit, and be sure it has not expired, too. Also, infections can occur, if you are at risk of pregnancy or not. So get checked for those if your pg test is negative.