Apologies as this could be a long one as I've been passed from pillar to post over the last 5 months

Back in October I had what seemed quite a large bleed from behind but as I was on my period put the blood down to that and said if it happens again I would go to a&e. Exactly 4 weeks later the same thing happened again so I went up to the hospital. They ran some bloods and had a little feel around up there. He said he wasn't concerned, it was probably just piles (which I've had in the past) and to come back if it happened again.
Fast forward to 3rd January and my gp followed this up with a phone call to see how I was feeling and anymore bleeding, which there hadn't been. She scheduled an appointment for 2 weeks time so she could have a face to face with me but again wasn't concerned about anything as I'd had no more bleeding or any pain. By 11th January I was in excruciating pain around my belly button and radiating into my right side towards my hip. I was booked in for more bloods, stool sample and a Ct at the end of the month. 
The bloods and stool showed slightly elevated inflammation markers which she again was overly concerned about but was waiting on the results of the Ct scan. They came back as a 10cm mass on my right ovary. To say I was shocked was an understatement! 
I was rushed through for more bloods and an gynaecologist appoint. I didn't make it that far, I had to take myself off to a&e again as the pain was unbearable, I was admitted as I was showing very high infection markers but again they weren't overly concerned until my ca-125 blood test came back showing an elevated level of 68. I had an internal ultrasound and mri which was showed as inconclusive so was sent over the mdt team to review. They felt the hospital I was in could proceed with the operation to remove and I was told my the surgeon it could be likely my raised tumour markers were due to the inflammation caused by such a large mass. The op went well and I was home with in 3 days. Everything was sent off for biopsy and I wait for the results. 
20th March the gynae oncology nurse called me to say I was being referred back to the mdt as the biopsy came back borderline cyst and possible precancer but I had nothing to worry about as I was likely to get regular checks. I had a letter the next day from the consultant saying exactly the same. The last sentence was 'This is nothing to worry about'
Everything was great, I felt amazing and returned to work 3rd April. 5th April the same nurse called back to same the mdt team looked at the histology and believe the cyst originated from my bowel and I was being referred back to the original hospital and the gi team. Ago she told me it was 'belts and braces' her words and I wasn't to worry. 
GI nurse called me last Wednesday to say they needed an up to date Ct scan and I would be seen by clinic once the Ct scan was back. She seemed a little vague so I asked should I be worried, her reply was what have you been told previously and I repeated the previous conversations with the gynae nurse. Alarm bells were going off but I put them to the back of my mind and went to work. 
a couple of hours later my world came crashing down. The gynae nurse called me back to say they now believe the ovarian cyst was cancerous and it is also in my bowel. To say I was shocked was an understatement. I can't get my head around having so many scans, bloods, stool sample and a weeks stay in hospital with abdominal surgery and they're telling me 8 weeks later they believe I have colon cancer

I've had the ct scan on Friday and awaiting my appointment with the consultant. I can't get passed how long it's taken them to 'find' this and how were they wrong just a few weeks ago when they told me it was nothing to worry about. I have 3 kids and I can't think about anything other than what are they going to do without me. I know how serious it is if it's spread and my head is all over the place. I've not slept and barely eaten, I'm so angry it's taken so long and so confused how they've missed it on so many times. 
My bloods are showing slight anaemia and folate level are a little low but my gp said this is common after surgery. My anaemia level is 110 so not that anemic but I'm on iron tablets now. 
I just don't understand any of it