I am losing my internet connection every 2-3 days. The computer is only put into hibernate during this period.
When I reboot the computer, the connection comes back.
My computer did not do this the first year I owned it.
I am connecting through a router. The other computers in the network do not have the same problem.
Note that actually loosing the internet connectivity during sleep or hibernate is by design, since during this period, all hardware would be disconnected to save power. Since you mention that this was not the case when you first got your system; you might want to check also with your laptop manufacturer since they may have specific power settings for that hardware to achieve this.
If you lose internet connectivity while the system is not sleeping or hibernating, then you could test setting your systems power management to maximum performance, some laptops may have some hardware sleep after certain time of usage or idle.