I had a Mirena a few years ago and had it removed as it made me feel awful - exacerbating peri as it tunrs out!
Anyhow, a few days later I had a bit of bleeding so popped my mooncup in. Then later that fternoon I had an enormous bleed. Blood running down my trouser leg in H&M and a long walk to the toilets in the shopping centre. I was soaked by the time I got there and thank goodness for individual cubicles with toilet, sink and hand dryer.
Be prepared!
In better news I felt a lot better without it almost immediately. I'm progesterone intolerant though so that may not be how you feel if you've been ok.
Have you seen a haematologist following your TIA? I have a blood clotting disorder and had a DVT at 30. My team are happy for me to have transdermal oestrogen and a Mirena-light called Jaydess. I take Dagibatran, brand name Pradaxa.
My new GP is freaked out by this arrangement and questioned the haematologists' support. GP thinks clot + hormones is a bad combo full stop. Haematology's rationale is that pregnancy is 100+ times the increase in hormones compared to non-pregnant but they don't advise not being pregnant, they prescribe anticoagulation to minimise risk of clotting.
With HRT, the added hormone is very small compared to pregnancy and as I am already anticoagulated (15 years and counting) I am minimising risk.
Clots are scary and for a whil it will feel like it's the only thing you think about - like a big black balloon right in your face. With time, it will drift away and be more on the edge of your vision. It takes a while and comes with feeling stronger physically and getting back to doing more normal things. Be patient with yourself and let anyone who offers you help, help.