Signatera positive - while still undergoing chemo?!?

November 2021, I had surgery for appendix cancer and my surgeon has been actively surveilling with blood tests and scans. Cancer markers were up in October and colonoscopy was done. I had had a colonoscopy about 20 months earlier.

Stage III-C adenocarcinoma of descending left colon was discovered. I had surgery and 13 inches of colon removed in February 24. Began Folfox chemo in April with 12 cycles prescribed.

CEA was 3.2 since test in May. Signatera in May was negative. Second Signatera test in August was positive- 2.59

I have had 3 rounds of chemo postponed because of low platelets and neutropenia, including this week's which would have been round 10.

My oncologist does not know where the circulating cancer DNA cells maybe trying to get a foothold.

My CT scans in July showed large thyroid nodes. I had a fine needle biopsy of the thyroid last week. Not enough cells were harvested to give a definitive answer and the slides have been sent for further analysis.

I also have had long COVID since 2022, chronic fatigue syndrome and fibromyalgia (diagnosed in 2015). Extreme fatigue. Anxiety and dread are also exhausting.

Any insights would be greatly appreciated!