Stuck mash

For some reason on today's brew the mash got stuck. I'd drawn off maybe a gallon and a half from the mash tun before it slowed to a trickle and stopped. Nothing I did would unstick it. The wort I had was about 1070 of so I diluted it down to 1038 and have about 2.5 gallons in the fermenter. I think this brew should be ok but now I'm concerned I have an issue for the next.