Years ago I voluntarily took several months off due to anxiety issues. I thought it would help me feel better and initially it did (in all honesty, I also had some guilt about this, too). However, going back to work was very difficult and, ironically, I had a load of anxiety about it.

I wonder if a brief reduction in your work schedule might be an option? You would remain in the flow but get somewhat of a break. Just an idea ...

I am on a sick note for "reduced hours" and "amended duties" (UK) at the moment. It has really helped me. I will ask for another one as I am not sure I can deal with work full time at the moment. My job is quite flexible though.

Hi,
I do not know about taking time off regarding MH issues, but this is my story. Last year I was suggested to take time off because of my health in general. I had a lot of stress because the position I held was with fair enough responsibilities and troubles. In addition to my physical disability, I have PKD. Stress is supposed to be a trigger for cyst grow. In fact, the last doctor before the one that suggested taking time off had told me to look for another job. It is not easy to find another job when you are disabled and a foreign visitor. And, like you, when I was suggested taking time off, I felt my supervisor would not like me taking time off because this would mean overloading for her. In addition, in the institution I work for people do not take long periods of time off usually. So, I did not do it. Then, I had to travel overseas for a long mission in several countries (all undeveloped countries) . When I came back I gota n unknown infection. Doctors could never find the source of infection, but I developed an inflamatory response that almost killed me. I was very sick for around six monts. Doctors told me to call my family and have somebody to come to the US because my condition was critical. And my supervisor and everybody accommodated. I feel that I had pushed myself too hard. My defense system was very low because of my stress and a perhaps silly infection produced an overreaction of my body. Or it was just the stress, because they never found the source.
I think the lesson I learned is that sometimes things get big in my head, I elaborate a lot of scenarios (terrible scenarios) and then I refrain from doing stuff (like taking time off, etc). Then sometimes reality obligues me to take that step, and things do not result as terrible as I imagine and I should have taken that step earlier. I could have died because of the way I elaborate.
OK, I do not know if this is similar to your situation, but I wanted to share this with you. I wish you the best

Remember you self certify for the first 7 days (this includes weekends and other days you might not normally work) so I would suggest that as a good starting point to figure out how you feel. Then take yourself to the doctor and discuss it further. It may be that just doing fewer days or shorter hours could be beneficial. Or a few more weeks off completly.