My suggestion is you need to be fully assessed, doing activities that are aggravating this should be a no no for now until you've got a better assessment from a physio...
you need your back,SIJ and hip examined, ur description suggests it could one of the following:
1) disc problem L5/S1 orfacet joint issue
2) tight/swollen piriformis pushing on the sacral nerve
3)Sacroiliac joint problem
having pain lasting the whole day is not a good sign and should be addressed. Do that quickly and reduce the risk of further hurting urself further...