Messed up period cycles

Hi there I have crazy messed up periods the last time I had my period was beginning of august and I just got my period 2night... I've always had a weird cycle, once I didn't get a period for 14 months.. I would get period like symptoms tho but no period... Im 27 now and this has been going on for the past I would say 5-8 years - I would be regular for 2-3 months getting periods on time and in sync then 2-3 months where it would be extremely late of missed that month completely... I'm not on any form of birth control have been in the past but that made things with my period a bit weirder only because when I would take my birth control pills a couple of days with taking it I would have my period again without having taken the full set of pills... If anyone can help me or make any suggestions on what I can do it would be greatly appreciated... I have went to drs and currently doing tests