Why has my fitness plummeted in the past 5 years?

Okay, let me start by saying I was always an athletic person growing up and very active in my teenage years. But when I was 21 something happened (that I don’t want to talk about) and I suffered from a mental handicap issue which greatly affected me psychologically, and I thought my life was over, I was still able to exercise my body but I WOULD’NT (because i was depressed because of my issue) and I was like that for the past 4 years. I was still active like I walked a lot to go places or going up steps. Now when I was 26 I started Jogging again and I noticed that I just don’t have that energy in me as before and I would run out of breath quicker. I also rejoined my Judo practice, and we do these summer salts which I used to have absolutely no problem doing , but now I get so dizzy doing them, I see the room spinning around me and I almost fall to the floor. THAT never happened to me before. And when I get to the stretching bit , omg my muscles are so stiff, I used to be able to do a near split, now its just so PAINFUL trying to do what I was once was able to do easily, and I can barely do like 130 degrees. Last but certainly not least its worth to mention that my sex drive has plummeted greatly (in comparison to before) like I can easily go for a month without ever feeling horny or want a “release”. Im 27 now and I feel like I doubt I am ever getting back my fitness again.
Is there something wrong with me or am I just getting older?