Should I go back to working full time?

I currently only work 24hrs a week. I started working part time once I returned back from my maternity leave last May. We have two daughters a 3 year old and a 10 month old. Due to our budget being so tight now, I feel really guilty about not going back full time. We don’t have to pay for child care because my mother and my husbands mother watches the girls for us. But their quality of care really isn’t that great, they think it’s okay to spoil them and allow them to do what ever they want (eat candy, unlimited screen time, not consistent with discipline), no matter how hard we push they think that’s what grandmothers are meant to do. My husband and I both agreed that only working part time would be the most beneficial for the girls. The only problem is now we don’t have extra money to spare, we can’t save or really do anything extra. I feel like the girls deserve more opportunities for vacations and other fun trips and me only working part time is hindering that. The only light at the end of this is that my husband just graduated from trade school and he’s looking for a new job that pays more. But what if he doesn’t find a new job as soon as we’re expecting? What are your thoughts? Advice?

UPDATE: Thank you for your responses! If I do go back full time, the girls would have to go to their grandparents. My biggest issue is that there is no structure at their houses. We have been going back and forth with them for 3 years and they still don’t listen.