Please go for lab test before take any antibiotics... It's not advisable to take any antibiotics without any specific indication.
Next Steps
1st of all go for basic investigation like CBC and Urine routine micro then if required you have to go for more lab investigation.. and after that take perfect antibiotics..
Health Tips
please share more information like abdominal pain, constipation or gastritis, headache or not so that I will suggest more specific lab test and treatment plane..
feel free to ask about lab test and treatment on chat.