It's Probably Just Me (Questions/Ranting) Advice Appreciated

As of late my friend has been avoiding me.
Actually let me elaborate; My friend, (lets call her Ann) has recently lost her step dad. I respect that she needs her alone time and I've given her plenty of that, 4 weeks to be exact, I'm trying not to become one of those clingy friends, but at the same time I don't want to lose her either. I've known Ann for 10 years, to say we were close would be putting it lightly, we've helped each other through the good and bad times, we've overcome depression together and we were always there for each other. However Ann has gotten a boyfriend and they've seen each other almost every other day in the past 4 months. I text her constantly asking how she's doing, if she's alright, if she wants to hang out for a little while or to just go out for some food. It seems through all my effort she has an excuse for everything. she wont be feeling well, or she's out of town, or her mom needs her to be with her that day.
We've both lost our dads and I know how hard it must be on her mother, this is a woman who is like a Disney princess, if all goes awry she throws herself onto the closest object and sobs, or if something doesn't go exactly how she planned she loses it and drops everything and just becomes an unsavory person to be around. So I can only imagine how she's dealing with the loss of her husband. However I'm beginning to become suspicious that Ann just doesn't need me anymore, or want me. I say this because I've been asking if she would like to hang out, at home, at the movies, grab some sushi, anything she wanted to do I would be up for. But she replied with "I'm just really tired and my mom needs me today, I should be good next week, we can hang then is that ok with you?" I reply with "no problem I'm up for whenever you want to get together." 2 days later I check on my facebook status and see pictures of her and her boyfriend going to a pumpkin patch. I get it that she wants time with her boyfriend. I've told her before that I'm cool of she just wants some alone time. So what I'm not understanding is that for weeks and weeks she's been too sick to hang out with me, but she spends almost everyday with him. She doesn't know that I know all of this, and what's pissing me off is that she's still avoiding me with the lame excuse of "her mom needs her".
I'd also like to throw in there that her BF and I hang out together, we've become good friends (and no before you jump to conclusions I'm no slut I'm very loyal to Ann and I would never do anything to hurt her, he and I just like to go out for coffee and play video games, she knows all this too) and he doesn't understand why she hasn't been hanging out with me either. Also it's not like she completely forgets about me, she sends me links to art sites, asks occasionally how I'm doing..

I don't think I've done anything to upset her, if anything I've helped her boyfriend understand some things about her (he doesn't have many friends so I'm usually the person he goes to when they're fighting to get some outside opinions or insight about the problems)

what she doesn't seem to understand or get is that I need her. She's one of my few friends that i trust yet she brushes me off like a pest or inconvenience. But when she calls I'm immediately there, yet when I call... I'm her last priority.
maybe its just me.. its not like the first time she's done this though.. maybe I've been replaced by him.. so she has someone else there for her now.
some insight would be helpful, what do you think? Am I overacting???