Izybat- how fast are you running? So many running challenges can be fixed by just slowing down. Like at the start of the run, slowing down when you are suffering is usually too late to save the run (but necessary, again, we've all been there). It's also very hard to progress if you are doing the same runs day after day. My running progressed significantly when I starting switching things up a bit. I had consistently been running 3 miles at the same pace basically 4 times a week. I was super good at running 3 miles at that pace. Faster? Not so good. Longer? Not so good. More runs? Meh.
So I made one mid-week run a little longer and a weekend run a 'long' run (meaning my longest run of the week, but not always a super long, 10+ mile run or anything!). I started taking one of the shorter runs and made it into a tempo run or I'd run intervals (on the road, no easily accessible tracks nearby!) or I'd run to the one legit hill and do hill repeats. Basically my weeks went from: Monday- 3 miles, Wednesday- 3 miles, Thursday- 3 miles, Saturday- 3-4 miles, to something more like: Tuesday- tempo/interval/hills day, Wednesday- 3 miles/recovery (Super slow, whatever pace my legs have in them depending on how hard I went the day before), Thursday- 5 miles/easy, Sat or Sunday- long slow run. I not infrequently would throw another short/easy run in there somewhere. It's not easy to get there though. I'm still struggling to get back after a spring of injuries/sickness/inconsistent training.
The one other thing I'd say is there is no shame in walking. It can be frustrating I know, but you do what you got to do to get the mileage in. If walking is what it takes, then walk a bit. Keep your walking pace up and don't walk too long. Quick break to get your breath under control and go again. For me, sometimes it's mental too. I think I need to walk so I do a systems check: Breathing? Not too bad actually. Shoulders? High and tight, lets relax those. Feet? Okay. Legs? Not terrible. etc. By the time I get to the end of my checklist I realize I just wanted to walk because, well, I wanted a break. But nothing hurts and my breathing isn't ragged, so I give myself a pep talk and make myself continue.
Also, if you are in a part of the world where summer is coming in, humidity is a killer! It always takes me a while to adjust and I always walk more during the summer.
TL, DR: Slow down, run different speeds/distances, walking is okay, do a systems check to see if you really NEED to walk (or just mentally want too), humidity sucks.