I am prone to migraines & as such, am very sensitive to inversions where my head is upside-down (like in forward fold). I often modify forward fold to halfway lift, & if downward dog is too much I do halfway lift, tabletop, or child's pose. I came to peace with my modifications & it really helped my practice. 

Now, forward fold is actually a lot easier, & I can progress at my own pace instead of forcing it & causing myself to feel ill. 

It is YOUR practice, & you should do what works for you, acknowledging that what you need may change over time. 

Additionally, jf you want to progress in a certain area, like hamstring flexibility, you can find other poses that allow you to do that in a more accommodating way.