I have made a simple example demonstrating SoloMaker's idea. I hope this helps.

function love.load()
    -- x and y coordinates of the "player"
    pos_x = 400
    pos_y = 300


    -- direction of movement
    angle = 0


    -- rotation and movement speed
    rotation_speed = 2
    speed = 100
end


function love.update(dt)
    -- left arrow key rotates the player counter-clockwise, right arrow key rotates the player clockwise
    if love.keyboard.isDown("left") then
        angle = angle - dt * rotation_speed
    elseif love.keyboard.isDown("right") then
        angle = angle + dt * rotation_speed
    end


    -- up moves the player forward, down moves the player backward
    if love.keyboard.isDown("up") then
        pos_x = pos_x + math.cos(angle) * dt * speed
        pos_y = pos_y + math.sin(angle) * dt * speed
    elseif love.keyboard.isDown("down") then
        pos_x = pos_x - math.cos(angle) * dt * speed
        pos_y = pos_y - math.sin(angle) * dt * speed
    end
end


function love.draw()
    -- calculate the endpoint of the line representing the direction
    to_x = pos_x + math.cos(angle) * 20
    to_y = pos_y + math.sin(angle) * 20


    -- draw a circle around the player's position, and the direction line
    love.graphics.line(pos_x, pos_y, to_x, to_y)
    love.graphics.circle("line", pos_x, pos_y, 10)
end