Hi- I also am currently in the midst of this (for the second time!) I am 13 weeks PP with my second baby, but also had PP thyroiditis after my first pregnancy with my daughter (born Jan 2017).
The main thing is, you have the diagnosis... for me, once I knew WHY I felt so awful, that alone brought a lot of relief. I spent the first 4 months of my DD’s life trying to work out what was wrong with me or, if indeed, there was actually anything wrong with me and it was just in my head/ part of being a new mum. I convinced myself I had some kind of terrible illness which hadn’t yet been diagnosed and my anxiety went through the roof. When I found out it was PP thyroiditis, I was just pleased that I hadn’t been imagining how I felt and that it wasn’t that I was struggling to cope with motherhood. My thyroid followed the classic hyper followed by hypo phases and lasted about 10 months total (at this point my levels had gone back to ‘NHS normal’... although I don’t necessarily believe that these levels work for everyone).
I felt far worse when I was hyper than hypo (which surprised me). When hyper, my symptoms were:
- Extreme fatigue and muscle weakness
- Racing heart/ palpitations
- Racing thoughts and anxious feeling (constantly feeling like something bad was just about to happen)
- Insomnia- could never get back to sleep after night feeds
- Hot and sweaty after the smallest of movements
Like you, I was told to take beta blockers but I chose not to. I got the prescription just in case I really felt I couldn’t cope but, in the end, the hyper phase just passed.
When I was hypo, my symptoms were:
- Tiredness but in a different way. It was more like a heavy, haven’t had enough sleep feeling than physical exhaustion. Several times had to call my mum to help look after DD, as I was just too tired.
- Dry skin, brittle hair and nails. Hair falling out.
- Depressive thoughts- lots of worries about my health and worries about the future
- Weight gain
I wasn’t prescribed anything for this phase as it was relatively short lived and I don’t think my levels were extreme enough to warrant it unless I really felt I needed it. I ended up going private to see an endo so was having quite regular and thorough checks.
I was told during my second pregnancy that it was ‘highly likely’ to return - at which point I sobbed to the endo because I was dreading going through it again and this time with a 3.5yo and a baby - and it has come back. However, so far it doesn’t seem to be anywhere near as bad. Again, I think a big part of this is that I knew what was going on as soon as I started to feel weird. I was told to wait until 8 weeks PP to get levels checked and, by this point, I already knew I was hyper. This was mainly thanks to my Apple Watch telling me my resting heart rate had risen by over 30 beats a minute in a space of weeks.
My tips for managing it and getting through to the other side would be to get all the help from family that you can- some days are worse than others and ask for help on these days so you can rest. Sleep as much as poss (tricky in hyper phase), because I always felt so much worse if I’d had a particularly bad night. Can your partner do a larger share of night feeds whilst you get through this? Drink lots of water to help stay alert. Take evening primrose oil to naturally balance hormones and, of course, vitamin D. Don’t do any aerobic exercise- it will make you feel worse and could be dangerous for your heart if the rate is already elevated
All of the other stuff (dry skin, bad hair, etc) can be lived with- I just try to tackle the exhaustion and manage the anxiety, which are the two most troublesome symptoms for me.
My blood is due to be tested again in 3 weeks time and I already feel like the hyper phase is passing. It will be interesting to see if I now go hypo again and for how long..?
It WILL pass and you will get back to normal again, but this condition really is a bit of a kick in the teeth when you’re a new mum!
Feel free to message me if I can help anymore- I’m by no means an expert, but I’m in the same boat right now 
I hope it’s a rapid cycle for you and you’re out of it before you know it x