Excitonic systems are challenging to deal with both theoretically and experimentally but in return, they offer a very rich physics and exotic features. We will investigate their properties under weak magnetic field and the resultant instabilities reminiscent of Sarma-I and Sarma-II phases. A new type of force in condensed matter physics, emerging due to the presence of the excitonic condensation will be demonstrated via semi-analytical and numerical calculations in two different systems of GaAs double quantum well geometries and layered transition metal dichalcogenide material 1T-TiSe2. Competition of charge-density wave and exciton condensate orders in layered systems will also be discussed in detail and an alternative explanation for the periodic lattice distortions observed in 1T-TiSe2 will be posed.