I'm well enough in myself (= happy) - I've just got this nagging headache. 我精神状态很好——只是这头痛的毛病一直没好。
I've definitely been feeling better in myself these last couple of days.
I've felt better in myself since I changed my diet.
I feel a lot better in myself and I put that down to my new regime.
I'm still quite tired but definitely better in myself.
See also: myself