Today I realised that my body strength has significantly decreased over the past year - embarrassingly so. I was in the park and I attempted to use some outdoor fitness equipment (it was a seated chest press - I think! 
) and I couldn’t do it. I could barely move it an inch. I’ve noticed that I can’t open jars as easily and things. I’m only 32, and this feels like a situation I need to sort out now before it gets any worse!
I don’t know why it has suddenly deteriorated so badly. The only thing I can think of is that I have a very physically demanding job (I work with people with very physically challenging behaviour) and I hurt my back at work in November last year and kind of just ignored it so maybe that has had an effect and I’ve been overcompensating somewhere and gone a bit wonky? I don’t know.
Anyway MY QUESTIONS:
What the hell do I do about it? Do I need a personal trainer? (Spendy) or can I do it alone?
This might sound like a silly question but what do I even ask for? What sort of strength do I need to even improve (all of it probably??)? Where do I start? Is there like a couch25k for this sort of thing? I’ve tried to google a bit but it all feels totally overwhelming. I’m a member of a gym but the weights and things in there feel totally frightening and I currently just swim and go to spin class.
Thanks in advance. Let’s get me ripped! 
or at least able to open a jar of pesto without having to ask my partner!