impressionable
Also, what do you call a person who is easily convinced?
gullible. adjective. a gullible person is easy to trick because they trust and believe people too easily.
Also question is, what do you call a person who is easily manipulated? capable of or susceptible to being manipulated; manipulatable.
Hereof, why am I so easily influenced by others?
Excess of empathy and lack of understanding. Those are main reasons for you to feel influenced by other people, more than lack of self confidence, in fact. If you feel this is your situation you could : Avoid contact with evil people.