Hi Suecee - is this the first HRT you have had in the 8 years since your last period? Not sure how old you are but as Dancinggirl says it normally takes a while for your body to get used to having oestrogen again.
If your mood continues to stay a bit iffy then it is possible you could be reacting to the progestogen in the patches which is given continuously for post-menopausal women. Some women get continuous low-grade adverse side effects from progestogens - but most women are fine as we don't hear from them on here!
I agree - you should give it 3 months and then see how you feel. Keep a mood diary so that you can look back and see any improvement - but don't go looking for trouble
Hope you continue to see an overall improvement as time goes on
Hurdity x