1. Stop feaking out.
2. Unless your doing kundalini exercises its not that great of a deal if your spine is not straight.
3. Your spine is naturally curved so straight means having your tail bone aligned with the bottom of your skull.
4. You can always lay on the floor making yourself comfortable.

Hope this helps you on your quest.

Brett.

The most common and well known of the meditation positions is the lotus position. The lotus position is also known as the Padmasanam position and is a position in which you sit cross legged. To accomplish this position, you need to be able to sit cross legged with your right foot on your left thigh while your left foot is on your right thigh. In this position, the soles of your feet should be upturned. This position was developed to open up the chest cavity for better breathing and also for promoting the stability of the body while using deliberation of thought to achieve a state of rumination. If this position feels tight or uncomfortable, do not force yourself to stay in it too long, but over time your body’s flexibility will increase so the position is more comfortable.