Are you describing this situation?
You were on your parents' Family HDHP for some months and then were on your employer's HDHP Self-only plan?
If you can be claimed as a dependent on your parents' return (it doesn't matter if you actually are claimed on their return, but only if you satisfy the requirements to be claimed), then you are not eligible to make any contributions to your HSA in 2018. In this case, you would enter "No" when asked if you had any HDHP coverage in any month in 2018.
If you can't be claimed on your parents' return, then just enter "Self". I assume that you did not contribute more than $4,350 to your HSA this year.
Second, was one plan your spouse's plan and the other your plan? If so, was the plan for either spouse a Family plan? If so, both of you must enter (per IRS rules) Family as your coverage for any month in which one of you had Family coverage.
If I haven't touched on your situation, then please make a new post in AXC stating your situation in detail:
- your HDHP type of coverage and for how many months
- your spouse's type of HDHP coverage and for how many months
- your HSA contributions (both through your employer and directly to the HSA)
- your spouse's HSA contributions (both through your spouse's employer and directly to the HSA)
- the amount of the excess
- whether or not either of you went on Medicare and what month
- whether or not (and the amount) of carryover of excess contributions from 2017 for either of you
