Welcome to HCM
We understand your concerns
I think there is nothing wrong with you. But with the given description, it is very difficult to say so.
You try to remember what was your physical condition before going to bath. If you take bath immediately after exercise of heavy meal, it is possible that you have sick stomach. Sometime along with cramps or pain. You must have experienced this and you got panicked. That is why the shaking. Don't worry. If you are so sure that everything was normal before taking back, do consult a physician for further advice.
You might need psychological counseling
., I am more than happy to provide telephone psychological counseling through healthcaremagic. Contact me through customer care, www.healthcaremagic.com.
Hope this clears your doubts. Available for further clarifications.