Syncope episode. Whom should i consult?

I am a 30 year old male working in IT. Last year I was diagnosed with deficiency of Vit D (8.4) and Vit B12 (152). I used to feel numbness in my hands and feet if I sit on them for a while. I used to feel dizziness if I get up all of a sudden. I took medication including injections but have been off it for a while (about 2 months). I haven't rechecked on my vitamin stats. I went for a trek with friends and slept on it for the night. Next morning I got up and went to bathroom and had sudden dizziness and went syncope for 2-3 mins. I have been alright since then but I want to consult a doctor about this but not sure whom to talk to. I have been planning a general health check up to check my vitals but not able to decide what all tests to opt for. Whom should I consult ? Are my symptoms worrisome for I have be fine before and after this episode. Please advice what to do and some pointers on my current condition. Thanks !!