Alternator bad?

So would that mean I would have to get a new alternator?

Based on your response to the expert’s advice I take it that you do not want to take it to a mechanic and you want to do it yourself. The problem is you likely do not have the proper equipment to test your charging system yourself and there is no way to know for sure if your alternator is the problem simply from describing the issue. Fortunately there are very few components to the charging system though. In the old days it was just the alternator, the battery, and a simple voltage regulator. Nowadays the current regulation is controlled by a more complex system but batteries and alternators haven’t changed much over the years and many auto parts stores will test things like starters and batteries for you. Anyway I would have the battery tested first. You see, although technically the alternator should be able to keep the car running normally even when the battery is bad this is not always the case. In fact my mothers Honda did all the exact same things as yours and it turned out to be the battery so it is possible. If that’s not it have the alternator tested and if that’s also good it means there is a problem somewhere in between the battery and alternator and you will have to have a mechanic sort it out for you. Good luck.