SPD diagnosis

If you have been diagnosed with SPD, how did you get diagnosed exactly? I’m sure I have it but my dr just brushed it off and said to wear a support belt. I’ve read every article possible and I’m doing all the tips to keep my pelvis stable but I’m still in excruciating pain. Epsom salt baths, support belts, exercises, pregnancy pillows, yet I’m in tears when I walk the shortest distance. Please tell me it goes away after delivery 😰 this is terrible and I’m so discouraged