What Causes Delayed Periods?

I have a regular cycle of about 28 days and have never missed a period in my life. I am 25 years old and have been taking the same birth control for nine years. My last period was april 28th i was suppsed to get my next one around may 26th although it never showed and i started to have early pregnancy symptoms i also bleed lightly or spotted a week before this. I took a some texts and they came back negative but symtoms persisted then around june 24th i should have gotten my period again and only lightly bleed for a day when i wiped then it was gone and still have symptoms.i have had issues making serotonin when i was younger and have iga nephropathy so am concerned i could be getting false negatives as i feel different could this be possible? I did miss some pills the last few months of my bc and started two or three packs late and me and my boyfrind did not use extra protection