Nothing yet (crawling or walking)

So my sweet daughter is 11 months old about to turn one and she still isn’t crawling yet or trying to walk in about a week ago she just started to but scoot and I don’t understand why because the doctor said she has good body tone and her muscles appear to be OK we took her to A physical therapist and they said she was a little bit delayed and we went and did multiple sessions with the therapist and she didn’t get any better and started to regress and was so frustrated I would cry the entire session that nothing was accomplished I’m kind of stumped on what to do and the doctor said if she’s not crawling by one then we’re going to have to go back and see the therapist and I just don’t know what to do and I feel like a failure as a mother and it’s very upsetting and I just don’t know what to do anymore