weird noise when hitting 2nd gear

hi! i have a 2011 toyota tacoma and for the past week or two it has been making a weird noise when it hits 2nd gear. it does not make the noise when hitting any other gears. its automatic, and when its making the noise it sounds like the engine almost gets louder? or is struggling? im not sure because i dont know much about cars. does anyone have any idea what this could be?