Not sure if you are still having trouble or not, but I found that any weapon that hits multiple times, like a spear, to be SUPER effective against him. And, for quick use, if you have healing potions on your hot-bar, you can just push H to heal instead of scrolling over to it each time you need it. A gun would be good to use, at your stage, if unable to get any souls to make the MegaShark, I would suggest using the clockwork assault riffle with possibly exploding bullets (you can look up the crafting recipe on the wiki) would help. Again, not sure if you are able to get souls or not, but try making a rainbow gun. It can hit multiple times for high damage. Any sort of minion can help with the drones. You can make an Imp Staff out of hellstone bars to summon an imp to help you fight. If you have the wizard, bu a blank book and get some cursed fire and make a cursed flames spell book. It does decent damage plus causes the Cursed Inferno! status effect.
If you have a crystal caves biome, try farming the chaos elementals (the teleporting dudes) to get a Rod of Discord. It will let you teleport to anywhere on screen, (if the space is big enough) at the cost of a little HEALTH instead of mana. Might make avoiding him easier. Let me know if any of this helped, and good luck!