To see a semi truck in your dream indicates that you are feeling overburdened or that you are being taken advantage of. You feel that you are pulling more than your own weight and it is time that others share in some of the responsibilities. Alternatively, the dream symbolises size, largeness and power.
Dreaming of an overturned semi truck indicates that there is an unexpected setback in your plans or goals. Perhaps you are taking on more than you can handle.