First, welcome back! Been a while since you've logged in. One of the first 1000 members, I'm glad to see you're still visiting.
Under certain circumstances the progress bar can lag... which doesn't effect the outcome of the test. I've seen this on VNC and on Android 2.x phones. When I've seen this it never pauses, then turns into a fluid progress bar (meaning that it moves smoothly). It will pause then JUMP... as if the browser couldn't keep up with the java used to update the progress. Regardless of how the progress bar updates the flow of data is uninterrupted. On the other hand you might have an issue that's causing this. If it pauses, moves, pauses... then the bar fluidly moves for the remainder of the test... I'd bet that there is something wrong.
First thing I would check would be MTU. You're on Bell South, which is DSL (right?)... PPPoE. Which means that the optimal MTU for your computer and router is 1492. Optimal MTU for cable Internet and most other providers is 1500. When I was on DSL for a while I was having a similar issue... my equipment was configured for my previous cable connection (I'm back on cable and don't miss fiber DSL at all, okay... the upload was pretty awesome. My connection on cable is much more stable and is especially much better for gaming. Plus, my nick is CA3LE... lol.) and changing the MTU resulted in a drastic difference. Like night and day. Check this out... CA3LE March to April 2010 -- you can see where I fixed it and stabilized my connection. (note that some of the results in that query are unrelated... TMN didn't have the filtering and identifying options back then so I can't narrow the search down to exactly the related tests. Only pay attention to the Qwest.net results). It's a very important setting and can have a profound impact on your performance. An easy way to tune your TCP stack in windows is with Speedguide.net's TCP Optimizer. But your router may also need to be configured correctly for PPPoE, it may have an MTU setting or may just ask you what type of connection you have. If you're coming from a different provider it's pretty common for this to be incorrectly set.
Here's a topic very similar to this one... Hanging while testing - I think his issue was resolved with a new NIC. So that could be the issue too.
A little side information, TestMy.net is different than the rest.
If you test on the majority of other Internet speed tests out there you may not see this effecting your results... because they've designed their tests to ignore the worst part of your results. I personally don't understand the mindset behind that, it shows where their interests lie... hint, they don't work for your best interest. TestMy.net on the other hand just calls it how it sees it. If there is a pause in the flow of information, it's reflected in the results.
Say that you download a 10MB file and it takes 10 seconds. Let's say that there is an extra 2 second pause at the beginning of that download. You might not notice it because once the download starts to flow it's going fine...... but does that mean that the 2 second pause never happened? Hell no! Even though it might have happened without you noticing, it still happened. In turn effectively dropping your speed for that download by about 17%. Now, let's say that you were downloading only 1 MB at the same speed, then the issue is compounded and effectively drops your speed by about 67%. I've had users, especially satellite users, that tell me that I should design the test to start the time after the speed has picked up... but wouldn't that defeat the purpose of the test? If your connection has pauses and blips, that's important information to know. It's the reason that you came here... right? You might stabilize at 8 Mbps (in our theoretical scenario) but that doesn't mean that's your real speed. Issues that cause that kind of problem make a HUGE impact on browsing speed, VoIP, gaming... etc. Ignoring that crucial information is exactly what most speed tests do, something TestMy.net will never do.