Do doctors issue medical certificate for a Leave para lang sa wellness and mental health?

Problem/Goal: My bosses agreed to give me a 2 week unpaid leave this december but they asked me to provide a medcert

Context: Id been super stressed with work, araw araw may 2-3hrs overtime and its taking a toll on my health. Eto ako now, may matinding ubo (di naman malala pero pumuputok yung tunog ng ubo) at medyo hinihingal narin. Sometimes I also find myself breaking down all of a sudden which never happened to me before. Ang lala ng anxiety ko. Nagpasa ako ng resignation letter yesterday morning, and nakipagnegotiate ung boss ko for me to take a leave for two weeks and come back on january pero magprovide nalang daw ako ng medcert para documented. Kung nagtataka kayo bakit unpaid ang leave, dahil under contract lang ako ng agency at wala kaming leave credits. I dont mind naman kasi sidejob ko lang ito pero lately feeling major kase. I told her how can I ask sa doctor ng medcert kung wala naman akong grabe na sakit? Dba? for mental health mainly and wellness ang reason ng resignation ko. Di ko pa naexperience to before so just asking here baka may idea po kayo. Kinonsider ko ung offer na magstay kasi wfh naman ito, and also ayokong magdecide abruptly. If after magpahinga eh dko parin gusto edi ppush ko na. So ayun, problem ko if how to ask for a medcert

my attempt: Wala pa. Dahil sa anxiety my mind is clouded so i appreciate any wisdom na sshare nyo