While that hasn’t happened specifically to me, any change in medication usage can definitely throw all kinds of stuff off. It’s certainly possible that the change caused you to experience an inability to divert your attention to/from a specific topic even if you know it’s what you need to do - especially if this is something you remember struggling with more frequently prior to starting medication in 2013.

However, (and feel free to ignore this unsolicited advice if you want) I’d warn you to be careful about confusing ADHD symptoms with your core personality. I take medication to allow myself to focus effectively enough to accomplish the things I need to accomplish, and it does that very well for me. But I still like to let some of my traits that are “very ADHD” (such as not always adhering to a strict schedule, instead following some of my impulses) run wild sometimes, because at the risk of sounding a little cliche, that’s just who I am. You might just be someone who wants a serious relationship, and wants to have a lot of frequent contact, and that’s okay. There are people who are simply like that, just as there are people who don’t ever want to be in a serious, exclusive relationship. Society tells us ADHD-esque traits are wrong and must be suppressed, which for an adult with a job is generally true. But don’t fall into the trap of assuming any trait you have that causes a problem should also be suppressed. By all means, introspect and figure out if this is just a medication issue, or if it is who you are. But don’t waste your life trying to suppress your own personality just because it isn’t perfect for everyone.