+1 to all responses. You are a 'victim' of the music education process. From the get go I bet that school bands to which you belonged practiced the same pieces over and over, perhaps you had to memorize half time shows. The band sounds good but you learned to play by ear and memory, which is not entirely bad, but does not develop sight reading skills. How the band sounds is the goal of the director, not necessarily the sight reading skills of the players. Most kids just want to play. Sound familiar?
Here's what helped me:
1) Back to 1 e, and, a, 2
2) Get some music staff paper (band director, internet sites have free downloads you can print off.
3) Write out a few measures of 1/16 notes, perhaps 2nd line G's or F's with one 1/16 rest and then the note on the 'e' syllable followed by two 1/16 rests. Throw in one or two one beat rests and then another 1/16 group on 'e'. Do this for a few measures.
4) Write more of the same for the 'and', 'a' and '2' syllables. This won't take long to do.
5) Play AND sing while looking at this musical figure. Writing your own material out is important to this. Anyone who has done transcription will tell you how valuable that work was.
6) Play this over and over, focusing on and connecting the syllable with playing the tone. Add this to every piece you play in band and practice on.
7) You focus for this time will be on reading the sounds on the paper, not how it sounds. Eventually you will see the figure and know how it sounds without thinking much - but what you really want to develop is playing on the correct syllable. It's just that simple. Break it down, play it correctly over and over, thousands of times and you will be golden. Knowing you are 'right' about the figures will drastically build your confidence and the others in your line will know you as the person who 'always' plays the notes at the correct time, always.
You are thinking, 'Hey, I saw this in my beginning trumpet books. You haven't told me anything new!' Yes, but as a young person did you really learn to associate the musical tone with the syllable ALL THE TIME? I bet not. Do this and you will never go wrong.