Problem managing voltage for sensors and LCD
TIP32 has very low hFe, 10-50 according to datasheet, so it needs high base current.
You need to lower the value of R10 accordingly, but honestly the best solution would be to replace TIP32 with a P channel MOSFET which will have a lower voltage drop when turned on and will not require drive current. Make sure to pick a MOSFET that has a RdsON value suitable for your application according to desired maximum voltage drop at the current you'll use, and the datasheet should specify this RdsON at a Vgs of 4.5V. If it is only specified for a Vgs of 10V then it will probably not turn on with your 5V gate drive.
Note you could alos remove the 555 and do the switching with the micro.