Cramps and back ache

6 weeks today and have been having chronic backache and cramping. Seen my OB and had a sonogram, all good, no bleeding. pregnancy progressing well. She can't work out what the cramping is, was in ER last night as cramping is so chronic all I can do is crawl into fetal position and cry and whimper. Taking Tylenol and have a warm hot water bottle to soothe but I'm getting super depressed as it's been bad for 5 days and night straight. I'm exhausted as I can't sleep through the night without a cramping episode. Is anyone out there experiencing this? I feel so alone. I heard it may be bad until 12 weeks when the placenta starts to take over. That feels like a million years away