It takes few weeks before the typhoid comes negative in blood.
Yes the vaccination exists and gives u immunity for 20 years or so. However , u would need to visit a doctor for the same as chemists rarely have much knowledge. Also , once cured properly, typhoid shouldn't happen again. Seems like u haven't treated yourself completely.
Next Steps
tests needed are - Typhidot IGM and Widal
Health Tips
if you want complete details , you can private consult me for the same.