Oh god OP I feel you. My first had silent reflux, it was hell. If the current meds aren't working, get on to GP and try something else. Ranitidine was a wonder drug for us, I know you can't get it ATM but there are other options.
EASY doesn't work for reflux babies because they need to be held upright after a feed, so that tends to be when they sleep. And then they can't be put down because it causes them physical pain. DD took all her naps on me, I would feed her, put her in the carrier and bounce her around the living room watching TV and then once she was out sloooowly sit down without taking her out of the carrier. You've probably tried that though.
I agree about the overtired thing, especially with reflux on top, that'll be tough.
I'm on maternity leave again now and the baby is so much easier but I still found last week a real drag when the weather was bad here. I think some people are forgetting that there's only so many walks you can do, and when the weather is shit there's no option to walk around a shopping centre, go to a cafe or meet a friend like I did with my first. It can get very very very boring.
At this stage, I had a list of three things to do for her (vit D drops, tummy time, top and tail) and three things for me (a walk, ten minutes of Pilates or similar and no snacks in the morning as I was feeling miserable about my weight). Rarely achieved all six but they gave my day some structure!
Mine both loved the play mat, especially with the TV on (my programmes, not kids stuff).
Online baby classes are better than nothing and several will give you the recording so you can do them when it suits. We sometimes do them a few times when the weather is bad. Just kills an hour and gives your day a bit of structure.
Lastly,I think those telling you to stop and smell the roses are forgetting the bomb your first baby takes to your life, even if they're easy. Nine weeks ago, OP was a whole entire, independent person. Now she's mummy, with no sleep, can't go to the loo without the baby screaming, can't eat a hot meal with two hands, can't remember when she last used her brain, etc etc etc. It's shit OP, just do what you need to get through and I promise it will get easier soon.