Here's my 2 cents on your dilemma:
Be careful - How much are you going to pay in realtor fees to get out of your house? Then there are 2 possible scenarios to consider:
If your house has appreciated: if you paid $250,000 for your house, and it is now worth $275,000. You are going to pay 6% for fees. This is roughly $16,500 in realtor fees. Any additional fees you would need to pay to close on the house would be extra. If your home appreciated - most likely the home that you want to move in has also appreciated 10%. So if the proposed house would have been $200,000 last year - now it is going to cost you $220,000. Would you really be happier - and have more cash flow in the "down-sized" house?
If your house has not appreciated in the last year - your $250,000 house would be sold costing $15,000 in realtor fees. This will most likely come out of your downpayment for your new house. What happens to your downpayment if it is ~15,000 less than what money you would expect to take away from the sale? Would that impact your downpayment for your new home?
Of course the current interest rates also affect everything. If you try to stick it out for a couple of years in your current home - it could be harder to unload a home when the interest rates are higher.
I would assume you have looked into refinancing? Are you currently getting the best deal you can? It sounds like you may be a SAHM. If you are - is there anything you can do to help out with the cash flow?
These are not easy decisions to make - there are many different options - that will impact you for years.
Good luck!
sorry for the long post pop daddy!