Quickly losing motivation for going to the gym

I’ve struggled with weight my whole life it constantly fluctuates. I go through phases of being physically active and not. I’ve been going to the gym on and off for the past few months. But I keep getting setbacks. Last month I was really sick for almost 2 weeks and had to miss the gym. This month I’ve been dealing with shoulder and neck pain and it’s been keeping me from going as well. I tried to go and do the elliptical without the arm workout but it still hurt my shoulder. I feel so defeated. I have weigh loss goals and want a flat stomach more than anything but my injuries are making it extremely difficult. I can’t do any of the ab exercises I used to because of it. I also get discouraged when I go to the gym and see people there in better shape than I am. I feel so self conscious. It’s hard not to compare myself to others. Ugh 😩 I wish I didn’t care so much and had more of an F it attitude