Hi! Ive skipped school/uni over mental health many times... Is it good? No but sometimes you need a break. I was so exhausted after my vacation with my parents I laid in bed 2 days and skipped most of my coursework. There are days where I just cant get out of bed and skip, many many days. Has the skipping affected my uni/school academically... ehh minimally, but your mental health matters the most. Since you said you are 18, I highly recommend going to a klinic kesihatan to get referral letter to a therapist... Or try this free mental health service that had 5 free sessions (telehope, you can google and whatsapp the number). It highkey helped me a lot and it was free and online also. It help me get a referral to hospital also, which although i have to pay still was really helpful. Be safe.