I know this reply is late in relation to your symptom and post, but today my father experienced similar symptoms as you've described and ended up in the ER.
1) Woke up rather hot with discomfort and profuse sweating.
2) Followed with routine morning bathroom run.
3) Felt dizzy and rather than fall down, he sat on the closed toilet set.
4) Last thing he remembers was he started to fall over and then blacked-out. (Syncope)
5) Mom found him, tried to arouse him to no avail just some moan, but clearly he wasn't conscious for at least 5-10minutes as he fell into the tub area.
6) 9-1-1 was called as she though he had or was experiencing a heart attack.
7) By the time the medics arrived - he was awake and conscious, they recommended he go get checked out at hostpital.
8) They checked him over but didn't find anything other than UTI (Urinary Tract Infection), he sugar was around 190 (as he's is a diabetic, but they didn't feel that was an issue), they CT scanned for other issues (but nothing was found), his BP was 160 over (don't recall the systolic).
9) He went home that day after stating earlier they were going to keep him over night for observation.
** So we still don't know the root cause for this issue, but as someone mentioned maybe related to his age, health and the UTI.
Don't think he had the swollen glands though, although some family member had Thyroid issues (Hashimoto's Hypothyroidism), but as far as we know he doesn't.
Did you ever get a Dx?