To add to what everyone else is saying, I shudder to think what would happen if, god forbid, something went wrong and you wound up involved in some kind of incident. You'd have to explain why you were working as a doctor whilst not employed, which may affect whether or not you're covered under nhs malpractice cover.
Too late now obvs. but don't ever let anyone push you around again.
As far as the "crying on shift" thing goes, ya, happens. My F1 year I had to go outside and have a cry a couple of times during surgical rotations. Then in A&E as F2 I distinctly remember a point where I nearly quit on the spot. Messaged my fiancée and everything. It shouldn't happen, but, especially when you're a fairly green doc (no offence), it's easy to get taken advantage of and find yourself overwhelmed. A big chunk of what separates a newly minted F1 from an SHO is being able to go "Meh, that's not getting done today" or "actually, that's not my job/patient" or "Well, this doesn't take priority at the minute" when the situation demands.