Looking (quickly) at the natal chart first, I see that Saturn in your 11th house is square your Sun, and in the Solar Return, the Sun is as mentioned by O - in the 12th house this year, feeling isolated and alone.
What is good to realize too, is that transits therefore, Solar Returns as well as temporary as conditions. We eventually move on past such and feel better again.
Your grades are decent, I'd believe your mother's words as she phrased them. She's okay with them. Let it go., don't hold on to what you "feel" is the truth of her being, rather "hear her" as she says, "hey sweetie, thats find, it's okay"...
In astro talk, the 11th house is a socializing house, and having your Saturn here, makes you "feel" restricted in this way via the 8th house Sun. Your Sun when you were born, is 0 Taurus, but in Sidereal is Aries - Aries likes to be the center of attention like Leos do. Perhaps being born with Sun on the cusp, is also something you'd need to come to grips with this way, - so I think this is temporary as for not "feeling" like socializing.
Its also okay for you to open up to your mom, tell her how you are feeling these days. It may help relieve a lot of this frustration you are experiencing.