The effects of living with RA as an 18 year old and how to help manage them

I have been diagnosed with RA for a few months now and am struggling with the side effects of it after coming off of steroid medication. I have experienced extreme fatigue most days even after getting a full nights sleep - has anyone else been getting this? I have also experienced brain fog/a fuzzy head whilst having problems remembering things. I was just wondering if anyone had any of the same issues and whether they have any tips of dealing with it (change of diet, physical activity etc) when I am not able to be very active due to the physical side effects of RA.