Check out ICU's protocol for systemic roundworms. If you are seeing some relief with a 3 day treatment from Vermox then you can probably get healed with a full real treatment.
First line: take 500 mg Vermox a day for 3 weeks. 250 mg at night, and 250 mg morning. With fatty meal, pill well chewed. Order from vrdrug.com
Take it for 3 weeks.
If that doesn't do it, go to Valbazen and Ivermectin. Ask on forum about it. Take Valbazen for 2 weeks with 4 days of Ivermectin per week. One week Vermox. Repeat with Valbazen and Ivermectin.
ICU's protocols say where to order from.
Sounds like you just need longer meds. Don't worry, it is safe. Many people have taken a lot more without issue.