There are a lot of reasons why you might puke during or after a workout. Not all of them are really negative PHYSICAL side-effects, but it's impossible to determine WHY you puked during those particular workouts without more information. You might be eating too soon before, eating too much, not eating enough, eating the wrong things before, have an adrenaline sensitivity, have any of a number of GI issues, weak sphincter at the upper stomach, etc etc... No way to know just based on one line of "I puked after a workout".
As a general rule of thumb, I tend to tell people that "Puking is your body's way of telling you that your workout is half over."
Getting it back is always harder. Just gotta stick with it. You do, however, have to avoid the circumstance where you overtrain and hurt yourself, or train so hard in small bursts that your recovery time between workouts is counterproductive. Ease back into it.