Feeling neglected by my best friend

I feel like my bsf doesn’t really care abt me anymore. she has a toddler so hanging out w her isn’t a guarantee ever, but i feel like i’ve given her so much of my time. when she was pregnant i would go out of my way to comfort her and take her to doc appointments- the dad was a vv close fam friend of mine but he was very abusive and an addict. throughout the pregnancy i was basically the dad, and he left her when my niece was 5mo old and i would help her out a lot even if it was just being there. she ended up getting into trouble w drugs and her baby was put w her mom while she was in rehab, i went and babysat my niece a lot and now she is 3. i’m so proud of where my bsf is rn, but she never seems to want to hang out and if she does she’ll give the baby to her dad (who’s clean and in her life again), i haven’t seen my niece in almost a month and when i ask if i can she’ll make a date and cancel and then say she’s so busy she doesn’t know when she can hangout. she does this w hanging out w just the two of us too, but it’s just been making me feel like she doesn’t see me as family or like i matter. i always seem to come last which is okay w me because i’m not blood family, but at this point i hardly get to see my niece anymore and it just hurts my feelings and makes me feel so unimportant, but i also feel as if i don’t have the right to feel this way because i’m not her blood family… i don’t expect to see her all the time or anything i just want to see her more than i do now. idk… am i being overly emotional? i know she’s a young single mom and it isn’t easy for her at all, but i just feel like she doesn’t really want to be my friend anymore… and she’s been my bsf since we were in 4th grade (20 now)