after using a nasal spray
is not unusual and it is possible your technique of using the spray is incorrect.
nasal sprays take about 4 weeks to start working and therefore using it upto (minimum) 8 weeks is recommended as a course. You can restart again but continue to use it for at least 8-12 weeks is ideal. WHile antihistamine or atropine
nasal sprays can be used on and off also on a regular basis.
You also need to get your allergies checked and only then we will be able to tell you when to start and stop the sprays.
Hope that helps.