I aspirated a decent amount of water by drinking & i choked pretty severely but am better now. is secondary drowning possible?

Unlikely: But if it were to happen, symptoms will develop 1 hour - 24 hours after your "drowning" incident. You will develop cough, difficulty breathing that gets progressively worse. If that happens, go to hospital. I'm glad you are better. I doubt that you have any more trouble.

Not Likely: Now that you are asymptomatic, secondary drowning is not likely. You should be careful if you develop cough or difficulty breathing within six hours of the choking episode. If either of these happen, you should be evaluated by a doctor. With your history of anxiety, it is important that you remain calm and use any relaxation techniques that you can to avoid an anxiety or panic attack.

Aspiration: Aspiration pneumonia can occur after inhaling liquids. Symptoms would include persistent cough, shortness of breath, chest pain, wheezing, abnormal sputum, etc. Drowning from aspirating a drink of water would be unlikely, and its a great sign that you are already feeling better.