This is not progress. This is you coming away from yet another conversation feeling responsible for his actions. To the point where you are diagnosing yourself with psychological problems and absolved him of needing to make even the token gesture you asked for.

His apology is a non-apology that still puts responsibility on you. He has laid the cause of the problem on you for not being open enough about your feelings, not him being an arsehole who not only failed to get you any sort of gift for Christmas, and then when you gave him a present didn’t do what any decent person would do and actually raise the issue of whether he had messed up himself. What you have done is smooth things over on the day, give him space to raise the issue when he may feel less embarrassed, and then when he failed to do that raised the issue with him like a mature adult does, including expressing your feelings. You have nothing to apologise for, and his miserable excuse for an apology is just further manipulation, reinforcing the idea that your feelings are somehow the problem and not his actions.

If you have been having mood swings severe enough for other people to remark upon them to you the most likely cause is this relationship, not any sort of problem with you. And if people have not been saying this to you directly, think carefully about where you get the idea that other people are saying this, because if that has ever come from things he has said to you it is an even bigger red flag than all of the others.