Why on earth is your mother messaging your boyfriend? Of course he thinks its "too much" because it is.
I wouldn't be a bit surprised that he is backing off from you because you're not grown up enough to handle your own affairs and you get your mommy to do things for you still.
Leave him alone for now and let him come to you when he starts to miss you. While you're waiting for him, work on your "fear of vomit." If you ever have kids you're going to need to get over that. Also Kindly ask your mother to stop messaging him and getting involved.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion