Carabeara.....hon.....you are really pushing that new knee. Did you read the articles from our BoneSmart Library that were posted for you earlier in the thread? If so, you would see that your body is in healing mode for a good 10-12 weeks after surgery. And that's if there are no issues that come up during recovery. You have two....the colitis and heading back to work a bit early.
You need to put yourself first here. This knee will be with you for a long time and you want to do recovery right. To do otherwise and push yourself too much can set your body up for a frustrating cycle of pain and swelling.
Here is my suggestion....if you absolutely MUST go to your job, then make that the only thing you do other than the gentle bends and stretches that MaryO recommended. All that activity getting ready for work (showering, dressing, making lunch, etc.) plus driving there and back, walking in and out of the office, sitting in training or meetings and being "on" for that length of time....that is ALL therapy!!! Don't let anyone kid you and tell you that you need even more exercise for that knee.
So, on a day that you work, that should be ALL you do. No errands. No cooking. No cleaning. No laundry. No going out. Come home and immediately get that knee up and covered in ice. Walk to the bathroom, bedroom or kitchen as needed, but that's it. Other folks can help or better yet just delay things that don't absolutely positively have to be done. If not doing it results in someone dead or injured or if it causes the house to fall in....okay....do it then.

But, otherwise.....YOU are your project!!!
As for meds, you need to get on some type of pain medication that you take on a regular schedule. I agree that you shouldn't be driving with the Lortab. But it may be possible with the Tramadol. You can supplement the Tramadol with Tylenol (dosage is 1000mg every 4-6 hours; no more than 4000mg in a 24 hour period.....be sure to count the acetaminophen in any other over-the-counter meds you take like allergy or cold meds). Bottom line is you need to get that pain under control! Consistent medication and lots of ice and elevation are the answer.
If possible, take ice packs to work with you and elevate your leg while you are sitting. You cannot over-ice as long as you keep something in between the ice source and your bare skin.
If your therapist will not understand that you are working your knee when you are going to the office, then you may need to stop therapy for a while (or for good). It's not really mandatory, you know. You could ask your therapist for printouts of the exercises they think you should be doing and tell them you want to do them on your own. That should be perfectly acceptable. Then if you really wanted to, you could check in with the therapist every week or two so they could report to the surgeon. Some doctors do like to have these progress reports. Don't listen to any of that talk about "windows." It is NOT true and we have many, many BoneSmarties to prove it! That includes me, as I gained ROM with both my knees for more than 6 months after surgery.
The ideal would be for you to take the full 10-12 weeks before going back to work. But, if you really cannot do that, please consider what I have suggested. It will not be a walk in the park because you are pushing yourself. But I understand that some people have financial requirements that dictate their early return to work.