Should I be finding things so difficult?

[Fifteenthnamechange]

I have 2 preschool aged DC who are in close in age.
My DH works away/travels a lot so isn't around much in week. I can never make plans or rely on him in week as his plans change last minute.
I have a part-time but very demanding & quite stressful job.it doesn't pay that well either, though I do like my colleagues & my working hours have been accommodated.
I feel stressed, overwhelmed & irritable a lot. I'm never paying full attention to anything-including my kids-cod I'm thinking of the 101 things I need to do.
I absolutely love my kids & want them to feel loved, hence working part time. But sometimes I feel like everything ounce of energy I have is taken up by their tantruming, grizzling & notstop demands. I'm not the most patient person naturally so it really can feel like a superhuman effort to not shout at them.
I just feel like I'm failing at everything. Is this normal?

As soon as I read 'two preschool children' I stopped and thought, yep, you're exhausted. Even without the 'part-time' job. It's normal - kind of - but you need a regular break and some support. Have you thought about putting them in nursery a day or two a week when you're not working so you can have a regular day to yourself?

It gets better as they get older and don't need to be all over you 24/7.

@ChopinIn10Minuets thanks for this. They're on a waiting list to go for a morning when I'm off. And my oldest does the half day in school nursery thing so that will help.
Just wish I could stop the cycle of feeling irritable then feeling guilty.
When I wrote it down I could see I'm under a bit of pressure, just dunno how to make it easier.
Have been thinking of changing job, so even if not less stressful it's better pay. But pt jobs are v difficult to come by aren't they

Anyone else?

It will get better, believe me. Preschoolers are notoriously stroppy and demanding. Maybe you've just got too much on your plate? I hope they sleep well so at least you're getting a good night's sleep.

My husband also worked long hours and travelled about 120 nights a year. So it was all on me. My kids are 20 months apart. I put my first into all day daycare when I worked, though my salary barely covered the cost. But it does get better. I put my second into all day nursery twice a week to give me a break, but I couldn’t have covered that on my salary alone. How are your financials - could you take a break from work altogether or pay for longer childcare? It’s physically tough at this age but emotionally tough when they get older. You should also talk to your husband about how overwhelmed you’re feeling. Any grandparents that could help out?
Ultimately you just have to bear with it. I have to say I have never been so angry as I have been since becoming a parent. It’s fine now (kids are teens) but it was awful and I felt I shouted at my son almost daily. My DH passed away when they were 4 and 6 and I just had to get on with it. But it’s never easy. Hang in there.

I'll know a df with 2 dd's, 9 and 3. I can hear him roaring at them when they visit. He says he can't have them both at the same time because they fight.