Here is what I think will help to understand the problems and what can be done to over come them
1) The delay in menses occurs due lot of stress
, worrying so this can explain why you are having 5 days delay in bleeding , the yellow/brown stuff is the endometrium/ Inner layer of uterus
which normally slough off during menstrual cycle so nothing to worry in that case
2) Here is the way to give a greater chances for becoming pregnant.
The process know as "OVULATION" is when the female egg releases from OVARY, this occurs roughly between the 15 th -20 th day after the menstrual cycle (end of bleeding ), pregnancy
means the meeting of the man's SPERM to the female's OVA- both have half genes which need to get together in order to form a complete structure, so the best possibility for the pregnancy is if the intercourse has occurred during those five days, other time their is no OVA present to meet the sperms hence no possibility of getting pregnant.
IF you have been having 30 days cycle so the best chances to get pregnant is during fertility
window while you are ovulating, for the best chances to get pregnant are from 16 days to 21 day from last menstrual withdrawal/ bleeding, ( if last day of menses is 14 march the the fertility window will be 1 april to 5 april ), more over the intercourse position is also important for the sperm have best possible chance to enter, mostly the female in bottom /missionary position is considered better, and keep lying for 30 min after ejaculation with the legs on the pillows and head flat to make incline position for sperm entry in the uterus.
Hope it helps.