Severe Vitamin D Deficiency

Assalamualaikum! I've been feeling extremely tired and low lately, plus experiencing significant hair fall. I decided to get my vitamin D levels tested and found out they’re at 7.1, which indicates severe deficiency. However, my parents aren’t taking it seriously, they believe I just need to eat healthier and I’ll be fine. But I genuinely feel awful, and even my bones hurt.

Can anyone recommend good vitamin D supplements available in Karachi? I’d really appreciate the help!