Ay napakahirap na situation na yan, mama! Honestly, what your OB is saying makes medical sense kasi kung irregular ka talaga, possible na nag-ovulate ka later than usual, so ang bleeding mo in April ay bago pa ang actual conception, it happens especially pag irregular cycles mo, kaya ang dating ng viability on ultrasound can be earlier than your last period suggests. Pero I get why you're confused and frustrated, lalo na kailangan mo ng med cert para sa SSS. Maybe get a second opinion from another OB para ma-clarify talaga kung paano nila makikita ang timeline mo, sometimes another doctor can explain it in a way na mas makakatulong sa iyo and sa documentation na kailangan mo, at least for your own peace of mind especially on your second pregnancy.