If you have a court order, then I suggest you follow it. Without a court order, either parent is entitled to custody of the child. You need to file a suit affecting parent child relationship to get legal clarification of the respective rights (including possession of the child) and duties (including child support and medical support or health insurance). Without an order, the father cannot compel you to surrender the child.
I am not intending this to be legal advice, because I don't know the particulars of your situation. Call me if you would like to discuss this or other isues.
If you do not have a court order you need to file as soon as you can. Since your child is under the age of three, the judge may order a temporary possession schedule that takes into account who has cared for the child since he was born, the effect on the child of separation from you, etc. If you do have a court order, you need to follow the terms but you may want to consider modifying it while your child is under the age of three.
This is not specific legal advice and does not establish an attorney/client relationship.