OK I need someone to see if they could help me with this one. I have 3 kids already.im trying for one more but this time my periods are off track they come every month but different times of each month.and sometimes they last longer than 7days.but what I can't get I took a plan be pill last oct.09 and every sense its been messed up really bad.do I still have a chance on getting pregnant?please help I'm trying to find a good doctor but no one is taking new patients right now.

In most cases, if you are having periods on a pretty regular basis, you are likely ovulating. However, with irregular cycles... although they are every month, it can be more difficult to determine when you are most likely ovulating. You could try having sex every two to three days throughout your cycles if possible. You could try watching for possible signs of ovulation... more fluid discharge, that becomes clearer... perhaps slight cramping sometime after you have already had a period.
If you have been trying since last October, it may just be a matter of more time. Most couples will become pregnant within a year of actively trying, but for a few it can take a bit longer.
Age might be playing a role?. and some women/men do experience secondary infertility... where they already have children but find it difficult to become pregnant again. Keep trying to locate a doctor that you can have a preconception appointment with. Good luck!