Thank you for sharing your dream. It sounds like you are experiencing a lot of emotions related to your recent loss and anxiety, and these feelings may be reflected in your dream imagery.

Dreaming of shopping can symbolize a search for something you desire or need, which in your case may relate to seeking comfort or normalcy after a tough time. The act of trying to find your size could represent your quest to find a sense of identity or belonging amid your grief.

The empty store and sketchy changing rooms may reflect feelings of isolation and unease, possibly mirroring your anxiety about being alone with your thoughts or fears. The staff member ignoring you could signify feelings of abandonment or lack of support during this challenging time.

Leaving money on the counter and escaping just before the door locks you in might indicate a desire to free yourself from overwhelming emotions or situations that feel confining. The transition from a quiet store to a busy mall could symbolize a return to social life or normalcy, but the dark outside may represent uncertainty or fear about the future.

Getting into a grey van with friends at the end of the dream suggests you are seeking companionship and support, which is crucial during times of grief. The grey color can symbolize ambiguity or a mix of emotions.

Overall, this dream might be telling you that while you are navigating through a difficult emotional landscape, it's important to seek support from those around you. It may also be beneficial to take time for self-care and process your feelings about your loss. If you feel comfortable, discussing your emotions with friends or a trusted adult can also be very helpful.