I'm having exactly the same problem! Mine last for 2 days this month and I'm usually a 6 day gal. If someone has an answer Id be mighty interested! I'm taking no meds and no longer using contraception though I'm pretty confident I'm not pregnant. The only thing we were using before is condoms anyway so they couldn't have messed with my hormones.
Mine were only 3 days sometimes 4 for the longest. Don't sweat it. The doctor saw no problem with it.
I guess you mean menstrual periods. Menstrual periods are usually said to continue for 5 days. By short period, may be mean that your periods finish within 4 or 3 days. I do not know if this will have any effect on your upcoming ovulation date which is suppose to be exactly 14 days after the day you finish your periods. I do not think you have anything to worry about; all women have different body types. I know a lot of women who have their periods only for 3 days have a cycle of 28 days and ovulate on the 14th or 15th day. If you are still worried, I suggest you visit your doctor and he can test your blood for any problems that could be.