Tumour markers still rising, clears scans. Anyone else?

Hello all. I would really appreciate someone talking me down !

I have had breast cancer twice (local) at age 34 and 37 (2012). Since the second time, I've had my ca153 tumour marker checked. It was around 10 for over 6 years (I'm 45 now).

They started gradually rising since last October and then going out of range. The latest results today are 78. I've had Pet/CT , bone scan and x-rays and they have come back clear.

I am currently on tamoxifen (over 9 years now - 100% er/pr, idc, her 2 neg, grade 2, stage 1)

The only symptom I have which is getting increasingly worse, is hip pain on my right side.

My Oncologist called today and said she thinks despite the clear scans so far, that the cancer has settled somewhere.

She said the Pet may not pick up small specs in my lungs for instance.

She has ordered a change of treatment from Tamoxifen to Zoladex and AI which I start next week.

She's also ordered an MRI of my hip as that Is my only pain. And it actually coincides with the timing of the markers rising.

I asked if it could be a benign condition causing this and she said not looking at the trend. It would stabilise or go down by now.

I feel very out of control .. I don't know what I'm dealing with and some straight talking answers would be very very much appreciated. Thankyou.