I'm sorry you've had such a difficult path through school, and with regard to your health. Before I get into the question of your formal testing, I do want to encourage you to keep a positive outlook on your future options. Although it may feel like you are irredeemably behind academically at this moment, you are not. Plenty of people go back to school much later in life than you are now to study all kinds of subjects, including topics even more complex than molecular biology. (I met someone once who started college in her late 70s, finishing her bachelor's degree in her 80s.)

With regard to your formal testing scores, there are a few factors to consider, on both the early testing and the recent testing. For the early testing, it is true that testing at about 5 years old cannot be considered extremely stable--but it also doesn't typically drop by 40-50 points, as you appear to be reporting. So even if it was slightly higher than your lifetime IQ would be projected to be, it probably wasn't completely out of the ballpark. I think we can safely say that the early measure established that you were notably above average in cognition, on the skills assessed, even if the extent is a bit vague.

The recent testing is also subject to some caveats. You report that you were not sleeping well, on a psychotropic, dealing with mental health issues, and disengaged from your education. All of these are factors that can affect the validity of assessment, especially of cognition, generally in the direction of lowered estimates. So generally, it should be taken with a grain of salt. Also, the newer WISC weights verbal and nonverbal tasks a bit differently than the old WPPSI did, with a bit more verbal on the old WPPSI than on the new WISC. So someone with a skewed profile like yours might see more of an impact on the FSIQ than someone with a more balanced profile would.

But I do see some patterns in your historical record of testing that are worth considering. Your history of group and individual testing is consistently higher in verbal areas, and weaker in nonverbal domains, which can be characteristic of certain types of learning differences. At the least, they suggest that you are likely to be most successful in areas that value verbal thinking and problem solving, rather than spatial (sometimes mathematical) thinking. Your testing profile appears to be average in math-related cognition and achievement, and above average in language-related cognition and achievement. That does not rule out molecular biology, by the way, as biology is not nearly as visual spatial a STEM field as, say, physics or mechanical engineering. It's harder to say whether the low processing speed score is meaningful, as that and working memory are the two cognitive domains assessed on the WISC that are the most likely to be affected by the interfering factors we've already listed. Functionally, of course, it had significance at the time, in terms of how efficiently you were able to produce volumes of work on demand. I don't know if that continues to be the case, or if conditions have changed.

Your negative elementary school experience could have been owing to any number of factors, including an unidentified learning disability (even in the context of above average intelligence). Actually, the 2e (twice exceptional) profile often feels the struggle even more than an evenly-developed slower learner, as the gap between your highest strengths and your lowest vulnerabilities is even more frustrating than just finding school generally a little bit more work. And GT programs tend to treat all gifted students as being globally moderately gifted, rather than being as diverse (or more) a population as the middle 68% are. Consider that you appear to have been underplaced in your language arts instruction, but either on-level or overplaced in your math instruction. Then you had about a half-dozen years of limited access to instruction, due to your attendance and social-emotional concerns, which would impact your acquisition of skills across the board. (BTW, even though the WISC is supposed to be a measure of ability, and not acquired skills, it unavoidably is affected by acquired skills--and hence access to instruction--as we use some acquired skills as proxies for native ability.)

In summary, the drop in assessed ability likely resulted from multiple factors, including lower score stability in young children, and interfering factors in early adolescence. You are still a capable young person with many possible good outcomes before you, and every right to pursue whatever healthy dreams you have.