Reading Voltage from my body?

Hi all!

First off, I'm completely new to Arduino, electronics, and the forum so this might be a simple answer...

Goal:
I'm trying to build a circuit with a tilt switch in it. When the switch is closed, I want the arduino to recognize it and turn on an LED.

Problem:
The circuit works, sort of. For awhile the LED was flashing for no apparent reason with the tilt switch in the open position. I disconnected the tilt switch section from the circuit completely and the LED would still flash. I discovered that if I grabbed a wire connected to a ground pin the flashing would stop and the tilt switch would operate somewhat normally. I say somewhat because it takes a few seconds for the arduino the recognize that the switch is open again when I tip it back.

EDIT: Oh also, if I bring my hand closer to the LED while not touching a ground wire, the flashing intensifies. If I move away from the LED, it calms down and stops.

Question:
What's going on? Is the arduino so sensitive that it's reading voltage from my body? I'm assuming that I'm doing something wrong here...

Set Up:
5V -> 3300? Pull up Resistor -> Tilt Switch -> Pin 12

Pin 4 -> 2200? Pull up Resistor -> Tiny lil green LED -> Ground

EDIT: Schematic Image Attached

Code:

#define led 4
int input = 12;
int count = 0;
int val = 0;

void setup () {

Serial.begin(9600);
pinMode(led,OUTPUT);
pinMode(input, INPUT);

}

void loop() {

val = digitalRead(input);

if (val == HIGH) {

digitalWrite(led, HIGH);
Serial.println(val);

}
else {

digitalWrite(led, LOW);
Serial.println(val);

}

}

Can you upload the schematic so that it would be much clear??`

Schematic Uploaded

Those aren't pull-ups, those are series resistors. That happens to be right for the LED (edit: although you might like to re-think the value), but you need to wire the switch something like this.

HTH....

You need this in "setup()":

  pinMode(input, INPUT);
  digitalWrite(input, HIGH);

This is a common issue reported here - input PINs float if not connected to some definite potential, which
is why pull-up or pull-down resistors (built-in or external) are required for interfacing to any mechanical
switch.

You are aware that you can do away without the Arduino ? There is no reason to have a microcontroller turn on an LED, the tilt switch can do that directly...

// Per.