Vector is an organism that do not have the ability to cause the disease itself but it carries the disease-causing organism and transfer it from one person to another person. One of the most famous examples is the female Anopheles mosquitoes.
Female Anopheles mosquitoes spread malaria. It gets the causative agent of malaria called plasmodium parasite from the blood of the infected person and transfer it to a healthy person through its saliva when it bites to a healthy person.
Therefore here mosquito played a role of vector in the chain of transmission.
It depends on what causing it. the only thing I can say is to drink plenty of fluids but I would recommend to go see a doctor, if you are unsure or worried.
