No..it is not safe and not recommended to continue Hypnotics (sleeping pills) continuously for such a long time.
As mentioned by you that sometimes you need to take 2 tablets shows that you have started developing tolerance to Alprax.
Next Steps
Try non pharmacological measures like meditation, yoga in the day time and/or read good books before going to bed.
Health Tips
Switch off your mobile phone or keep it away from you at least 45 mins before your sleep time.