Rapid weight loss advice (long)

I know this has been asked before, and it can be a lot of things.
Bear with me please.

TLDR; at the bottom

It is the weekend and mind is racing.

I, m42, 6ft2…have been battling obesity for a good part of my adult life; started tirzepatide about 3 years ago, and up till 2 months ago I had lost about 90lbs with a combination of tirzepatide, better eating habits, exercise.
All good till then my weight loss was slow and steady, no bad symptoms.

3 years ago I was about 320lbs…2 months ago I was 237lbs.
I reached the highest dose of tirzepatide (15mg/week)and have been tapering down in the last few months to about half that..

Since mid July , the only changes I have implemented was to start measuring my food to hit a certain goal of macros (high protein and carbs, lower fat).

I also started fasted walking about 4 miles on day and 4 miles on Sunday (only have done this over 3 weekends, not today).

1 month ago I weighed in at home and was about 230lbs, so about 7 lbs in a month, but it didn’t surprise me much, like mentioned I have been measuring food and eating between 1700-2400 calories, going to the gym 4x week, and now walking, so thought it was all good.

Well, on 7/29 I was still 230lb.

Again; have not changed anything else:
Next time I weight in was this week, on 8/6: 224lbs

In another situation I’d be ecstatic, but I have “not been trying that hard” to explain 6lb loss in 1 week.

Well, that freaked me out and reached out to my PCP office and I scheduled an appointment with a gastroenterologist nurse , for next Thursday.

Last evening 8/7, at around 6pm, I weigh in, 222.4!!!

My mind is racing, wife noticed, she told me to go to urgent care last night, went, they did some basic blood work and actually gave me fluids; all basic blood work came back positive (I can post if needed); like literally the people there said “I wish I had these results“…

I weigh in coming back from fluids and a light snack, back to 224.

I weigh in this morning, 221.2!!!!

Freaking out…worried it wait till Thursday…

Freaking out: blood work does not show anything wrong, but this is not normal.

NO OTHER SYMPTOMS, up till this Monday; regular appetite, regular gym sessions, no bowel movement changes, no blood on stool, no pain in stomach…literally only the weight loss.

Precisely after I started worrying; my appetite has gone down and anxiety way up (I do not have any psychological ailments, do not take anything like that since I don’t need it) in the last 2 days, which I would think it’s not helping my weight.

What specialist or where to reach out to, to take a look at what’s going on???? Besides the gastro.

FAMILY HISTORY:
No immediate cancer in my family; one aunt on my mother’s side had some ovarian or cervical cancer but she’s cancer free.

Mother: still alive in her mid 60s, she had gall bladder stones issues and had emergency surgery in her 40s.
She does have depression issues and has been fighting that for as long as I remember.

Grandmother on my mom’s side:
She had a thyroid issue during her adult life that would in effect caused her to lose weight fast…then she would bounce back.
Later in her 50s had to had a surgery to remove something from there, I was young and do not know the specifics I do remember her scar in the neck

Uncle, mother side: thyroid issues, seems sudden, lost weight too, but he was an alcoholic, and did not treat any of this, died in his late 40s

Multiple members on my moms side had the gall bladder extracted.

Father:
No cancer on his side, he has had high lipids that doctors detected in his late 30s early 40s.
Diagnosed with non alcoholic fatty liver, but controlled.

WIFE:

Did have HPV when young and it provoked uterine cancer, caught early and treated; has had std testing every year since then, clear.

ME:
Never smoked, drink very seldomly (couple of times a year), obesity.
When obese I did have high lipids and high liver enzymes.
They have lowered as I lost weight, all in range now.

Started TRT 2 years ago, so I am on testosterone.

I do have a pilonidal cyst that cause flair ups here and there during the last 6years.

Did 23 and me years ago, and it did not detect anything about BRCA, but it did state some risk of celiac disease.

MAY BE RELEVANT:
earlier this year; I had some kind of swelling in the inner part of my right butt cheek (close to the anus), touched it and it felt like a cyst but it never popped up, went away in a couple of weeks)….this came back in the last 2-3 weeks, not as painful and swollen as the first time.

TLDR;
- Lost 8-9lbs since 7/29, of those , have lost 2 lb per day in the last 2 days.
- NO other symptoms, no pains, no blood in stool or urine etc
- No direct cancer (parents) history
- family history of thyroid and gall bladder issues
- No change in bowel movements etc (at least not up till Monday this week, maybe stress causing less appetite in the last 2 days)
- No fatigue
- Had HPV vaccine first shot 7/7, second shot yesterday. Next shot will be January.
- bloodwork everything in range of normal

What is the right specialist I should reach out to, to fast track finding out what’s going on?

Thanks for reading