I was able to breasfeed my baby exclusively for 2 months when I fell sick and had a terrible headache. I ate panodol and since then, my milk supply has dropped drastically. Now, I am only able to breastfeed him at night. Even if I let him suckle, I don't get the simulation at all now. Isn't panodol safe for breastfeeding? Also, I read from books that there is some form of medication which could help increase milk supply. How can I get those medication?

Panadol, when taken at recommended dosages, should be safe for breastfeeding. It should not affect human breast milk production.
It is possible that your breast milk production fell because you were ill, and was breastfeeding much less frequently during this time.
With patience and determination, you may be able to rebuild your milk supply. Put your baby to both the breasts during each feed. “Comfort between” feedings are also encouraged. Preparations which may further increase breast milk production include fenugreek (www.breastfeeding.org/articles/fenugreek.html), available from many health food stores and metoclopromide (www.drugdigest.org). The latter can only be dispensed with a prescription from a registered medical practitioner