Hopeful, HRT will cause bleeding (usually) for the first 6 months - randomly perhaps. So taking it for 2 days really wasn't giving it much of a chance. You need to commit to taking it for at least 8-12 weeks before you know if it is working and even then there may be some bleeding for 6 months, even if you are post-menopausal. That is totally normal. If it doesn't settle down, it gets heavy or painful, then go back to the GP as you might need it adjusted. But 2 days really isn't enough time at all, by anyone's standards. You might also get other side effects, which again typically settle. Hormones can cause all kinds of issues when you change or start them but time is all that is needed for things to settle. Usually.
If atrophy is really bad, it could cause some spotting but usually in response to friction (sex, putting something up there etc) - not just by itself, I wouldn't think.
Use the Vagirux pessaries (should be a loading dose of every day for the first 2 weeks) and the estriol cream outside, mixed in with some YES OB or Olive and Bee. If you do get some stinging when you put the cream on, you should know that it is only stinging because you have microscopic cuts down there due to dryness. It's the same as if you had a cut on your hand and you put some antiseptic cream on it - it would sting. But that doesn't mean you shouldn't put the cream on, or it won't get better. Same goes with the estriol cream. It MAY sting a little at first, but don't feel that is a 'bad' sting - it means it is helping/working and needed! You can reduce the chance of it stinging if you mix it with YES OB or Olive and Bee, so you use less of the estriol at first and more of the moisturiser and then gradually increase the estriol...
I wouldn't suggest using Canesten unless you actually have thrush, because it's known to make dryness worse...