Feeling Like a Burden in My Relationship

sometimes I just feel like utter garbage for being in this relationship. I've been with him four and a half years now but sometimes I think he'd be better with someone who isn't like this. isn't like me. he's got his own issues of course, he gets migraines occasionally and he had adhd but it's all feels like little things, things that feel easy to work on and compromise with. all my nonsense feels so much like a horrible burden to place on him. I havent brushed my own hair in months. I can, but my arms get tired and hurt after just a couple seconds holding them up, and brushing my hair and getting it into a ponytail is almost at a limit with what I can handle. my arms ache so much afterwards. when I mentioned that to him, offhandedly, he offered to start brushing my hair before work, so I wouldn't have to deal with it. and hes done it since. it's. he's so sweet and just offers to do these things. I know his love language is acts of service so he doesnt mind doing the small things for me, but even so it just doesn't feel like he should have to, or that I'm not doing enough for him in return. I dunno. I worry about it a lot I feel like.