Bleeding on and off in early pregnancy

Today I am 6 weeks and 5 days.

I did a Frozen Embryo Transfer (one embryo) on Nov. 11. I’ve had spotting (brown) on and off since 4 weeks. The doctor said it was fine and normal. Then had my first ultrasound this past Monday. There was a baby and a healthy heart beat. Then the next day I felt a gush of wetness, went to the bathroom and it was blood and a clot. I put a pad on and called the fertility clinic in hysterics. They told me to come in right away to see what was happening. Got there, they told me to take off clothes waist down and as soon as I did blood was all over their floor. Doctors nurse came in and gave me another vaginal ultrasound. Just when I thought all was over, there he was with a strong heart beat. They looked for a bleed in my uterus but couldn’t find one. They said they didn’t know why I was bleeding. All I could do was hope for the best and wait until next Monday’s ultrasound. I’ve been taking 1 ml of progesterone injections once a day. They just added the progesterone suppositories once a day. The day of the large bleed, it slowed down and eventually stopped later that night. Then all day yesterday it was barely there and light brown. This morning it’s barely there but more red than brown. This is driving me insane. Has anyone had this before and delivered a healthy baby??