The taxability with your gain has nothing to do with what you plan to do with the money after, they are two separate transactions.
If you have unforeseen circumstances that create a financial hardship, you can claim a partial exclusion. This is based on the number of days divided by 730 (number of days in 2 years). Your exclusion would be the shortest of
- the number of days you owned the home
- the number of days you lived in the home as your main home
- the number of days since you last used the exclusion.
So for 600 days of ownership, you could exclude 600/730, or 82.2% of the usual $500,000 exclusion, which would be $410,000.
To qualify for the partial exclusion, you need to show unforeseen circumstances that create a financial hardship. There are some specific safe harbors (situations) that qualify, but situations not specifically listed may also qualify. If you claim the exclusion, you don't send proof of your circumstance with your return, but keep the proof for 6 years in case of audit. The partial exclusion rules are described in publication 523.
https://www.irs.gov/pub/irs-pdf/p523.pdf
