Hello there! Thank you so much for checking out Crimson Hydrangea and leaving a comment! As someone who is also very anxious and responsible, I completely understand your plight and my heart goes out to you. <3
Unfortunately when it comes to Day 2, you'll have to choose between helping Rita or going to the seashore. Because of time and story constraints, there currently isn't a plan to be able to do both activities in Day 2.
That being said, in Day 3, you WILL have the option to go to the beach/ seashore in at least 2 of the routes/options. Technically, you should be able to explore/get both of the options even if you helped Rita in Day 2. However, they will depend on a few other actions/ questions in the game, but I won't say much more in fear of spoiling what I have planned haha.