Sounds like your light is too far away.

When the light is too far away the seedlings begin to stretch towards it.

Lower the light and watch how the plants react. You are looking for 1 inch between each set of leaves.

Get a fan to blow on them about 15 minutes every 2 hours. The fan will work wonders.

Also, you can lightly bend the plants stems to make them stronger in the beginning. But be gentle.

Thats the best advice I can give you right now.

Let us know how it goes.

Take care.