Hi Kathleen
It will be very obvious the contrast between the oestrogen only and then when you add the progesterone as utrogestan has to be taken in such high doses to ensure enough gets to the womb.
If your oestrogen is low then the obvious symptoms are a return of flushes and sweats but some anti-depressants also help with flushes and sweats for some women and I think you are taking them? That being the case this will mask these symptoms so it won't be so easy to tell. Other symptoms of low oestrogen would be low mood - but this can also be caused by progesterone, joint aches, palpitations etc.
This is why it's good to take these hormones cyclically at first so that you can get to know how you feel on oestrogen only and then adding the prog.
When I am on the utrogestan phase of my cycle I feel exceptionally tired especially in the mornings (more than usual), and sometimes progessively foggy-headed and lethargic, sometimes a headache - if unlucky a migraine. Some women feel pms like symptoms - irritability, anxiety etc too, but anxiety is also a symptom of low oestrogen!
You would notice these symptoms on the progesterone only part even if taken vaginally.
You won't necessarily be progesterone intolerant - different progestogens affect women differently, and also taking them all the time can make the symptoms build up and persist whears when you take it cyclically you have a blast and then finished.
In your position I would not go 8 weeks cyclically yet. Personally I would start with a normal length cycle (eg a calendar month) because you want to see what sort of bleed you get, unless you know what your womb lining thickness is? If you haven't had a bleed for years then going 8 weeks might be quite a shock especially if you absorb the gel very well - some women achieve quite high levels on only two pumps. Also will depend how big you are and your BMI - the taller/larger you are the more a given dose may be diluted!
If your bleed is OK after a couple of cycles I would gradually increase by a week so that you get to the right length for you that lets you have the oestrogen dose you want but without a heavy bleed..
For example I rarely go 8 weeks - it is more usually 7 or between 6.5 and 7.5 depending on what I'm doing when I'm going away. It's great though as it gives you flexibility and once you know how your body behaves on this regime you can time your cycle accordingly!
Most women will experience some progesterone withdrawal symptoms - so classic pmt, maybe a headache, etc over the next two or three days as the progesterone leaves the system and the physiological changes are reversed. Once this has passed you should feel great!
Hope it all works out for you and look forward to hearing how you are doing

Hurdity x
PS a cycle of 8 weeks is not oestrogen only for 8 weeks - that is the total length of the cycle - so would be oestrogen only for 6 weeks and 2 days. A cycle of 6 week means 4 weeks and 2 days of oestrogen only. The cycle is counted either from the first day of the prog or the first day of the oestrogen only - and includes all the time on oestrogen only together with the time when prog is added. Going 8 weeks on oestrogen only and then 2 weeks of prog would be a cycle of around 10 weeks....