Constipation/gas!

LuEll
Oh man my stomach has bed a hot mess. In the morning I am fine. A little gassy. But then I go to the bathroom one or two times within two hours. Then I'm good to go! Feeling like a champ! That is until about 7 at night and I start welling up with gas and can't fart or go to the bathroom! I through three times tonight that I had to go like now and only thing that happened was a little toot 😫 and my belly hurts so bad too! But I'll fart through the night and start it over in the morning. My dr today told metal take miralax every morning. I'm worried I am going to have diarrhea or something because normally I go so easy in the morning anyways. It's just the constipation and gas in the evenings. Thoughts?