Use visualisation and visualise white-gold energy entering your body. If you have problems doing this too, you can face the sun with your eyes closed OR not looking directly to it and try visualising it like that.
Like this you can also visualise energy coming from the sun to you as you do the foundation meditation.
Another thing would be to go somewhere closer to nature or somewhere that is usually less negative energy, and visualise the white-gold one (or the color you desire except of grey) entering your body.
Program yourself to absorb the energy directly from the Sun. There's a change you are accidentally breathing in energy from other people who have bad energy. Also clean your aura first, if there is dirt on your aura then you might be breathing it into yourself. You can quickly clean your aura while outside in the sun, just affirm that the powerful sun energy is thoroughly cleaning your aura. And then you can breathe it it, and affirm that it is healthy and beneficial for you