4 weeks post op extended Tummy Tuck, is it normal for the drains to be still in?

You should deathly follow your physicians instructions. For your course of treatment and recovery having a drains for four weeks does not sound atypical.

Your experience sounds like a tough one. Generally, I try to
remove drains before 4 weeks but in certain situations I might leave them him
longer. The drains are unpleasant but there is no significant risk to leaving
them in longer. That said, at some point they will have to be removed. Often if
one drain is less than 30cc I decide to remove it and leave the other in place. However, these
decisions are ones that have to be made by your surgeon. I don’t see a benefit to bed rest. Sometimes you can infuse a sclerosant through the drain and the
use of a compression garment to try and stop this process.

So sorry to hear about your post-operative course.  Extended abdominoplasties are really big surgeries and I am sorry you have had to go through so much.  After that much blood loss and hematomas, your body gets into a pro-inflammatory state and excess fluid production is not uncommon at all.  The swelling that your body wants to get rid of does so through the path of least resistance, which for you now is your abdominal drains.  I encourage you to get up and move around to prevent DVTs and need to wear a compression garment to help things along.