Feel drained and horroble

I am 12 weeks 2 days ... this is my third baby. I am pushing 30. I badically feel bad and tired everyday. My other two pregnancies were in my early 20’s. Do I feel so bad this time around Bc I am soo much older this go around? Does anyone else feel like this ? I feel like I am being a horrible mom to my 11 year old and 5 year old . Help please