I'm going to play devil's advocate (and I don't at all mean this is a negative way just some thoughts based on my own experiences)....you mention in the original post "Just me being a nice person." While of course there is nothing wrong with being nice my thought was - well why do you feel you need to be nice? And I don't mean that mean at all - I used to do nice things for others (rather than myself) to feel better about me so that's why I asked....and what I found through counseling and therapy was that was me not feeling good about me and trying to get that good feeling by helping others (it didn't work I had to find myself and my own inner confidence to find that feeling). So while helping can be a good thing it can also be not so good sometimes is what I learned. For me I believe that nice/helping thing (while neglecting me) was what kept me stuck in my alcoholic marriage about four years longer than I wanted to be there.
Instead...I started doing nice things for myself...once I did that I felt better about me and more confident, now am I never nice to others? Of course not but I don't make a conscious choice to do so instead if in the moment I feel it in my gut I do it, otherwise not. For me that has been very healing...now maybe that doesn't work for everyone...but how about treating yourself to a nice dinner and a nice manicure/haircut or whatever? Just my two cents to take or leave.
Of course I give but I've found I can't give to others until I take care of myself first.
PS - I used to feel guilty too - in counseling I learned that that was conditioned into me through my childhood with a narcissistic personality disorder mother and an alcoholic father. The only way I unlearned that behavior was through a wise impartial counselor.....that's not the only way of course just my path.