The UK's communications regulator Ofcom has released a free app to test the quality of your wireless network. It is possible for you to have a poor signal from your phone, tablet or laptop computer just because the wireless router is positioned near to other electrical equipment or is obscured by walls. Even simply restarting the router can help, if there are other wireless networks around that could be interfering with your own signal.
To work out whether you do have a problem, download the iOS app or the Android app. You can also read more about it on this Ofcom news page.